[CI] Add criticality of release to release notes (#1259)

* Enforces presence of C-labels to designate the importance of a release
* Iterates over them on a release, takes the highest present and includes it in the release notes
* Lists the change(s) that caused the release to be that priority

polkadot/scripts/gitlab/check_labels.sh

@@ -3,21 +3,43 @@
 #shellcheck source=lib.sh
 source "$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )/lib.sh"
 
+ensure_labels() {
+  for label in "$@"; do
+    if has_label 'paritytech/polkadot' "$CI_COMMIT_BRANCH" "$label"; then
+      return 0
+    fi
+  done
+  return 1
+}
+
 # Must have one of the following labels
-labels=(
+releasenotes_labels=(
   'B0-silent'
   'B1-releasenotes'
   'B2-runtimenoteworthy'
 )
 
-echo "[+] Checking labels for $CI_COMMIT_BRANCH"
+criticality_labels=(
+  'C1-low'
+  'C3-medium'
+  'C7-high'
+  'C9-critical'
+)
 
-for label in "${labels[@]}"; do
-  if has_label 'paritytech/polkadot' "$CI_COMMIT_BRANCH" "$label"; then
-    echo "[+] Label $label detected, test passed"
-    exit 0
-  fi
-done
+echo "[+] Checking release notes (B) labels for $CI_COMMIT_BRANCH"
+if ensure_labels "${releasenotes_labels[@]}";  then
+  echo "[+] Release notes label detected. All is well."
+else
+  echo "[!] Release notes label not detected. Please add one of: ${releasenotes_labels[*]}"
+  exit 1
+fi
 
-echo "[!] PR does not have one of the required labels! Please add one of: ${labels[*]}"
-exit 1
+echo "[+] Checking release criticality (C) labels for $CI_COMMIT_BRANCH"
+if ensure_labels "${criticality_labels[@]}";  then
+  echo "[+] Release criticality label detected. All is well."
+else
+  echo "[!] Release criticality label not detected. Please add one of: ${criticality_labels[*]}"
+  exit 1
+fi
+
+exit 0