[CI][WIP] Fix check_labels (#3039)

* fix check_labels

* runtime change test. revert me

* Revert "runtime change test. revert me"

This reverts commit 6bec7e34f522555f9ac84332721c191d547bdf16.

polkadot/.github/workflows/check-labels.yml

@@ -19,3 +19,4 @@ jobs:
           GITHUB_PR: ${{ github.event.pull_request.number }}
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           HEAD_SHA: ${{ github.event.pull_request.head.sha }}
+          BASE_SHA: ${{ github.event.pull_request.base.sha }}

polkadot/scripts/github/check_labels.sh

@@ -54,7 +54,7 @@ else
   exit 1
 fi
 
-if has_runtime_changes origin/master "${HEAD_SHA}"; then
+if has_runtime_changes "${BASE_SHA}" "${HEAD_SHA}"; then
   echo "[+] Runtime changes detected. Checking audit (D) labels"
   if ensure_labels "${audit_labels[@]}";  then
     echo "[+] Release audit label detected. All is well."