Update push.yml (#186)

Use a better way to get the tag to see if it should be an official build

.github/workflows/push.yml

@@ -351,7 +351,8 @@ jobs:
       - name: NuGet Pack
         shell: pwsh
         run: |
-          $officialBuild = '${{ github.ref }}' -match '(?<=^refs/tags/v)\d+\.\d+\.\d+.*$'
+          $tagName = git tag --points-at HEAD
+          $officialBuild = $tagName -match '(?<=^v)\d+\.\d+\.\d+.*$'
           $officialVersion = $Matches.0
           $wipBuild = '${{ github.ref }}' -match '^refs/heads/.*-wip$'
           $ciBuildOnly = $wipBuild -or ('${{ github.ref }}' -match '^refs/heads/(?:master|.*-servicing)$')