Version.targets,GithubCI: upload pre-release pkg

Upload pre-release package on `main` branch using
nugetPreRelease.fsx to get a version number that
includes the date and commit hash inside it.

.github/workflows/build-gtk.yml

@@ -29,18 +29,20 @@ jobs:
             chmod 764 $WORKLOAD_MANIFEST_DIR/*
             dotnet workload search
             dotnet workload install gtk --skip-manifest-update
+      - name: Generate pre-release version suffix
+        run: dotnet fsi nugetPreRelease.fsx "" > PreReleaseVersionSuffix.txt
       - name: Build MAUI
         run: |
             sed -i 's/_IncludeAndroid>true/_IncludeAndroid>/g' Directory.Build.Override.props
             dotnet build Microsoft.Maui.BuildTasks.slnf
             dotnet build -c Release Microsoft.Maui.Gtk.slnf
       - name: Pack MAUI
         run: dotnet pack Microsoft.Maui.Gtk.slnf
-      - name: Upload binaries to nuget (if tag, and nugetKey is present)
+      - name: Upload binaries to nuget (if tag or main branch, and nugetKey is present)
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           NUGET_KEY: ${{ secrets.NUGET_KEY }}
-        if: ${{ env.NUGET_KEY != ''  && startsWith(github.ref, 'refs/tags/') }}
+        if: ${{ env.NUGET_KEY != ''  && (github.ref == 'refs/heads/main' || startsWith(github.ref, 'refs/tags/')) }}
         run: dotnet nuget push **/*.nupkg --api-key ${{ secrets.NUGET_KEY }} --source https://api.nuget.org/v3/index.json --skip-duplicate        
 
   dotnet-format:

eng/Versions.targets

@@ -86,6 +86,9 @@
       <PackageVersion>$(PackageReferenceVersion)$(VersionMetadataPlusLabel)</PackageVersion>
       <!-- Generate stable release package for tags -->
       <PackageVersion Condition=" '$(GitTag)' != '' ">$(GitSemVerMajor).$(GitSemVerMinor).$(GitSemVerPatch)</PackageVersion>
+      <!-- Pre-release version for other cases -->
+      <PreReleaseVersionSuffix>$([System.IO.File]::ReadAllText($(MSBuildThisFileDirectory)../PreReleaseVersionSuffix.txt))</PreReleaseVersionSuffix>
+      <PackageVersion Condition="$(CI) and '$(GitTag)' == '' ">$(GitSemVerMajor).$(GitSemVerMinor).$(GitSemVerPatch)$(PreReleaseVersionSuffix)</PackageVersion>
     </PropertyGroup>
 
     <PropertyGroup>

nugetPreRelease.fsx

@@ -0,0 +1,6 @@
+#r "nuget: Fsdk, Version=0.6.0"
+
+let args = fsi.CommandLineArgs
+
+Fsdk.Network.GetNugetPrereleaseVersionFromBaseVersion args.[1]
+|> System.Console.WriteLine