Updating Sonar Github action

Author: danny-gallagher

.github/workflows/sonar.yml

@@ -22,10 +22,10 @@ jobs:
           github.event.pull_request.head.repo.full_name == github.repository ||
           github.event_name != 'pull_request_target') }}
         run: echo "Unsecure PR, must be labelled with the 'safe' label, then run the workflow again" && exit 1
-      - name: Setup .NET Core
-        uses: actions/setup-dotnet@v1
+      - name: Setup .NET 5
+        uses: actions/setup-dotnet@v1.9.0
         with:
-          dotnet-version: 2.1.700
+          dotnet-version: 5.0.x
       - name: Setup java
         uses: actions/setup-java@v1
         with: