chore(ci): fix windows ci env restore

See actions/runner-images#1090

Author: piksel

.github/workflows/pull-request.yml

@@ -55,6 +55,11 @@ jobs:
       with:
         dotnet-version: '3.1.x'
 
+    # NOTE: This is the temporary fix for https://github.com/actions/virtual-environments/issues/1090
+    - name: Cleanup before restor
+      if: ${{ matrix.os == 'windows' }}
+      run: dotnet clean ICSharpCode.SharpZipLib.sln -c ${{ matrix.configuration }} && dotnet nuget locals all --clear
+
     - name: Restore test dependencies
       run: dotnet restore