Revert "workflows: add concurrency group to check-by-name workflow"

This reverts commit 75600cde6b.

.github/workflows/check-by-name.yml

@@ -16,13 +16,6 @@ on:
     # so it shouldn't be a problem
     types: [opened, synchronize, reopened, edited]
 
-# Create a check-by-name concurrency group based on the branch name. if a new
-# commit is pushed to the main branch while a previous run is still in progress,
-# the previous run will be cancelled and the new one will start.
-concurrency:
-  group: check-by-name-${{ github.ref }}
-  cancel-in-progress: true
-
 permissions:
   # We need this permission to cancel the workflow run if there's a merge conflict
   actions: write