Update actions/setup-dotnet action to v2 (#3119)

Author: renovate[bot]

.github/workflows/NetCoreTests.yml

@@ -54,7 +54,7 @@ jobs:
 
     - uses: actions/checkout@v2
     - name: Setup .NET
-      uses: actions/setup-dotnet@v1
+      uses: actions/setup-dotnet@v2
       with:
         dotnet-version: 6.0.x