Remove old CI workaround, update .NET 6 SDK

Author: yaakov-h

.github/workflows/build.yaml

@@ -24,10 +24,7 @@ jobs:
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: 6.0.100
-
-    - name: Workaround for https://github.com/dotnet/core/issues/5881
-      run: dotnet nuget locals all --clear
+        dotnet-version: 6.0.423
 
     - name: Build WTG.Analyzers
       run: dotnet build src --configuration ${{ matrix.configuration }}
@@ -54,10 +51,7 @@ jobs:
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: 6.0.100
-
-    - name: Workaround for https://github.com/dotnet/core/issues/5881
-      run: dotnet nuget locals all --clear
+        dotnet-version: 6.0.423
 
     - name: Build NuGet Package
       run: dotnet pack src -p:CommitID=${{ github.sha }}

.github/workflows/release.yaml

@@ -26,10 +26,7 @@ jobs:
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: 6.0.100
-
-    - name: Workaround for https://github.com/dotnet/core/issues/5881
-      run: dotnet nuget locals all --clear
+        dotnet-version: 6.0.423
 
     - name: Create NuGet Packages
       run: dotnet pack src --configuration Release /p:CommitID=${{ github.sha }} /p:TagVersion=${{ steps.tag_name.outputs.result }}