fix sntax

Author: trgibeau

.github/workflows/ci.yml

@@ -21,8 +21,8 @@ jobs:
       uses: actions/setup-dotnet@v2
       with:
         dotnet-version: |
-          '6.x'
-          '8.x'
+          6.x
+          8.x
 
     - name: Restore dependencies
       run: dotnet restore Microsoft-Perf-Tools-Linux-Android.sln