(#284) add net7.0 to CI pipeline

Author: nils-a

.github/workflows/build.yml

@@ -50,13 +50,16 @@ jobs:
         run: git fetch --prune --unshallow
 
       # codecov and unittests need 2.1, gitversion needs 5.0
+      # GitReleasemanager needs 7.0
+      # builds run on 9.0
       - uses: actions/setup-dotnet@67a3573c9a986a3f9c594539f4ab511d57bb3ce9 # v4.3.1
         with:
           dotnet-version: |
             2.1
             3.1
             5.0
             6.0
+            7.0
             9.0
 
       - name: Cache Tools