Check for singular 'benchmark' in commit message

[skip benchmark]

.github/workflows/build.yml

@@ -88,7 +88,7 @@ jobs:
             continue
           }
 
-          echo "skip_benchmarks=$($msg.Contains('[skip benchmarks]'))" >> $env:GITHUB_ENV
+          echo "skip_benchmarks=$($msg -match '[skip benchmarks?]')" >> $env:GITHUB_ENV
           break
         }