Remove concurrency because we already have it

Author: xgreenx

.github/workflows/ci.yml

@@ -20,9 +20,6 @@ env:
 
 jobs:
   rustfmt:
-    concurrency:
-      group: rustfmt-${{ github.ref }}
-      cancel-in-progress: true
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3