Update GitVersion.Portable.nuspec

Author: SimonCropp

src/GitVersionExe/NugetAssets/GitVersion.Portable.nuspec

@@ -8,7 +8,7 @@
     <owners>nservicebus, simoncropp</owners>
     <licenseUrl>http://www.opensource.org/licenses/mit-license.php</licenseUrl>
     <projectUrl>http://github.com/Particular/GitVersion</projectUrl>
-    <iconUrl>https://raw.github.com/Particular/GitVersion/master/Icons/package_icon.png</iconUrl>
+    <iconUrl>https://raw.githubusercontent.com/GitTools/GitVersion/master/docs/img/package_icon.png</iconUrl>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
     <description>Derives SemVer information from a repository following GitFlow or GitHubFlow.</description>
     <language>en-AU</language>