make release pipeline build 8+9

Author: baronfel

.github/workflows/release.yml

@@ -17,8 +17,7 @@ jobs:
         with:
           dotnet-version: |
            8.0.x
-           7.0.x
-           6.0.x
+           9.0.x
           include-prerelease: true
 
       - name: remove global.json so that 7.0 builds
@@ -30,7 +29,7 @@ jobs:
       - name: Run Build
         run: dotnet pack -c Release -o ./bin
         env:
-          BuildNet8: true
+          BuildNet9: true
 
       - name: Get Changelog Entry
         id: changelog_reader