Fixed wrong sorting of prerelease versions

As recommended in a NugetGallery issue about the same problem

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
       uses: PaulHatch/semantic-version@v4.0.3
       with:
         short_tags: false
-        format: "${major}.${minor}.${patch}-prerelease${increment}"
+        format: "${major}.${minor}.${patch}-prerelease.${increment}"
     - name: Restore dependencies
       run: dotnet restore
     - name: Build