BLD: Fix regex in arm64 wheel builders (pandas-dev#51326)

Update config.yml

Author: lithomas1

.circleci/config.yml

@@ -39,7 +39,8 @@ jobs:
             elif [[ $TRIGGER_SOURCE == "scheduled_pipeline" ]]; then
                 export IS_SCHEDULE_DISPATCH="true"
             # Look for the build label/[wheel build] in commit
-            elif (git log --format=oneline -n 1 $CIRCLE_SHA1) | grep -q '[wheel build]'; then
+            # grep takes a regex, so need to escape brackets
+            elif (git log --format=oneline -n 1 $CIRCLE_SHA1) | grep -q '\[wheel build\]'; then
                 : # Do nothing
             elif ! (curl https://api.github.com/repos/pandas-dev/pandas/issues/$CIRCLE_PR_NUMBER | jq '.labels' | grep -q 'Build'); then
                 circleci-agent step halt