Fix parse error

Author: JakeGinnivan

appveyor.yml

@@ -12,7 +12,7 @@ build_script:
 
   - cmd: msbuild GitVersion.sln "/p:Configuration=%CONFIGURATION%;Platform=%PLATFORM%"
 
-  - ps: & "/GitVersionExe/bin/$env:Configuration/GitVersion.exe" /l console /output buildserver /updateAssemblyInfo
+  - ps: "./GitVersionExe/bin/$env:Configuration/GitVersion.exe" /l console /output buildserver /updateAssemblyInfo
 
   - cmd: appveyor PushArtifact "NuGetExeBuild/GitVersion.Portable.%GitVersion_NuGetVersion%.nupkg"