Remove concurrency group

Author: lukekim

.github/workflows/pr.yml

@@ -7,10 +7,6 @@ on:
       - trunk
   workflow_dispatch:
 
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref_name }}-${{ github.ref_name == 'trunk' && github.sha || 'any-sha' }}
-  cancel-in-progress: true
-
 env:
   CARGO_REGISTRIES_CRATES_IO_PROTOCOL: sparse
   CARGO_NET_RETRY: 10