Add "$ProgressPreference = 'SilentlyContinue';" to Windows-based variants

[tianon]

As pointed out by @StefanScherer in #116 (comment). 👍 ❤️

See also PowerShell/PowerShell#2138 (comment) (linked in a comment within this change) for more details.

[StefanScherer]

LGTM :-) Keeps the rest of the Dockerfile clean.

[tianon]

Indeed 👍

Here's some of the build output (just to show that this really does work, and doesn't break the build):

$ docker build 'https://raw.githubusercontent.com/infosiftr/golang/803439af1f04d215135fff8ca406761ead9f06af/1.8/windows/windowsservercore/Dockerfile'
Downloading build context from remote url: https://raw.githubusercontent.com/infosiftr/golang/803439af1f04d215135fff8ca406761ead9f06af/1.8/windows/windowsserverDownloading build context from remote url: https://raw.githubusercontent.com/infosiftr/golang/803439af1f04d215135fff8ca406761ead9f06af/1.8/windows/windowsservercore/Dockerfile 3.526 kB
Sending build context to Docker daemon  5.12 kB
Step 1/14 : FROM microsoft/windowsservercore
 ---> f49a4ea104f1
Step 2/14 : SHELL powershell -Command $ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';
 ---> Running in 0fb6ecb9555c
 ---> 1da716bfb422
Removing intermediate container 0fb6ecb9555c
Step 3/14 : ENV GIT_VERSION 2.9.2
 ---> Running in 7c62a775cf1f
 ---> 8aa50eb3635c
Removing intermediate container 7c62a775cf1f
Step 4/14 : ENV GIT_TAG v${GIT_VERSION}.windows.1
 ---> Running in 6d74695b5ada
 ---> c0897bd058f6
Removing intermediate container 6d74695b5ada
Step 5/14 : ENV GIT_DOWNLOAD_URL https://github.com/git-for-windows/git/releases/download/${GIT_TAG}/Git-${GIT_VERSION}-64-bit.exe
 ---> Running in dd35b92c4156
 ---> 89715b743df6
Removing intermediate container dd35b92c4156
Step 6/14 : ENV GIT_DOWNLOAD_SHA256 006d971bcbe73cc8d841a100a4eb20d22e135142bf5b0f2120722fd420e166e5
 ---> Running in 94c47dba1bb7
 ---> 523305cff712
Removing intermediate container 94c47dba1bb7
Step 7/14 : RUN Write-Host ('Downloading {0} ...' -f $env:GIT_DOWNLOAD_URL);   Invoke-WebRequest -Uri $env:GIT_DOWNLOAD_URL -OutFile 'git.exe';                Write-Host ('Verifying sha256 ({0}) ...' -f $env:GIT_DOWNLOAD_SHA256);   if ((Get-FileHash git.exe -Algorithm sha256).Hash -ne $env:GIT_DOWNLOAD_SHA256) {      Write-Host 'FAILED!';            exit 1;         };              Write-Host 'Installing ...';    Start-Process           -Wait           -FilePath ./git.exe    -ArgumentList @(                         '/VERYSILENT',                  '/NORESTART',                   '/NOCANCEL',                    '/SP-',                '/SUPPRESSMSGBOXES',                                             '/COMPONENTS=assoc_sh',                                                 '/DIR=C:\git'          );               Write-Host 'Updating PATH ...';         $env:PATH = 'C:\git\bin;C:\git\mingw64\bin;C:\git\usr\bin;' + $env:PATH;        [Environment]::SetEnvironmentVariable('PATH', $env:PATH, [EnvironmentVariableTarget]::Machine);        Write-Host 'Verifying install ...';      Write-Host '  git --version'; git --version;    Write-Host '  bash --version'; bash --version;  Write-Host '  curl --version'; curl.exe --version;              Write-Host 'Removing installer ...';   Remove-Item git.exe -Force;              Write-Host 'Complete.';
 ---> Running in d33cac2dded5
Downloading https://github.com/git-for-windows/git/releases/download/v2.9.2.windows.1/Git-2.9.2-64-bit.exe ...
Verifying sha256 (006d971bcbe73cc8d841a100a4eb20d22e135142bf5b0f2120722fd420e166e5) ...
Installing ...
Updating PATH ...
Verifying install ...
...

$ docker build 'https://raw.githubusercontent.com/infosiftr/golang/803439af1f04d215135fff8ca406761ead9f06af/1.8/windows/nanoserver/Dockerfile'
Downloading build context from remote url: https://raw.githubusercontent.com/infosiftr/golang/803439af1f04d215135fff8ca406761ead9f06af/1.8/windows/nanoserver/DoDownloading build context from remote url: https://raw.githubusercontent.com/infosiftr/golang/803439af1f04d215135fff8ca406761ead9f06af/1.8/windows/nanoserver/Dockerfile 1.652 kB
Sending build context to Docker daemon 3.584 kB
Step 1/9 : FROM microsoft/nanoserver
 ---> 787d9f9f8804
Step 2/9 : SHELL powershell -Command $ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';
 ---> Running in 1786686054a4
 ---> f68134b58739
Removing intermediate container 1786686054a4
Step 3/9 : ENV GOPATH C:\\gopath
 ---> Running in dafd0b198c3b
 ---> dfd658b33527
Removing intermediate container dafd0b198c3b
Step 4/9 : RUN $newPath = ('{0}\bin;C:\go\bin;{1}' -f $env:GOPATH, $env:PATH); Write-Host ('Updating PATH: {0}' -f $newPath);   setx /M PATH $newPath;
 ---> Running in 985bf054639e
Updating PATH: C:\gopath\bin;C:\go\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Users\ContainerAdministrator\AppData\Local\Microsoft\WindowsApps

SUCCESS: Specified value was saved.
 ---> 7f2e54e78a33
Removing intermediate container 985bf054639e
Step 5/9 : ENV GOLANG_VERSION 1.8beta1
 ---> Running in 844ffdd47ce5
 ---> 029dd8ffde1e
Removing intermediate container 844ffdd47ce5
Step 6/9 : ENV GOLANG_DOWNLOAD_URL https://golang.org/dl/go$GOLANG_VERSION.windows-amd64.zip
 ---> Running in 27ec0c9b2400
 ---> 38ec60c7aefe
Removing intermediate container 27ec0c9b2400
Step 7/9 : ENV GOLANG_DOWNLOAD_SHA256 7b246c37dfe37348a16b6bc1865ebc21a79c4fd869032fba78c65e46b11b741b
 ---> Running in 0e31f203266e
 ---> 85ccb3914682
Removing intermediate container 0e31f203266e
Step 8/9 : RUN Write-Host ('Downloading {0} ...' -f $env:GOLANG_DOWNLOAD_URL); Invoke-WebRequest -Uri $env:GOLANG_DOWNLOAD_URL -OutFile 'go.zip';              Write-Host ('Verifying sha256 ({0}) ...' -f $env:GOLANG_DOWNLOAD_SHA256);       if ((Get-FileHash go.zip -Algorithm sha256).Hash -ne $env:GOLANG_DOWNLOAD_SHA256) {              Write-Host 'FAILED!';           exit 1;         };             Write-Host 'Expanding ...';      Expand-Archive go.zip -DestinationPath C:\;    Write-Host 'Verifying install ("go version") ...';       go version;            Write-Host 'Removing ...';       Remove-Item go.zip -Force;              Write-Host 'Complete.';
 ---> Running in 15b62e81ab78
Downloading https://golang.org/dl/go1.8beta1.windows-amd64.zip ...
Verifying sha256 (7b246c37dfe37348a16b6bc1865ebc21a79c4fd869032fba78c65e46b11b741b) ...
Expanding ...
Verifying install (go version) ...
go version go1.8beta1 windows/amd64
Removing ...
Complete.
...