ci-cd: Use dotnet SDK v8 in code test job (required for ubuntu-runner…

… v24) (#423)

* Bump ubuntu-runner & add workflow to path for trigger

* Revert tp 22.04 for build-and-analyze.yml

* Re-test with 24.04

* In .NET setup action, use dotnet-version 8.0.x

* Set ubuntu-runner ver back to latest

.github/workflows/build-and-analyze.yml

@@ -17,7 +17,7 @@ jobs:
         uses: actions/setup-dotnet@v4
         with:
           dotnet-version: |
-            6.0.x
+            8.0.x
       - name: Build & Test
         run: |
            dotnet build Altinn.Receipt.sln -v m