ci: check that commit messages follow Conventional Commits format

.github/workflows/convetional-commits.yml

@@ -0,0 +1,13 @@
+name: Conventional Commits
+
+on:
+  pull_request:
+
+jobs:
+  check-conventional-commits:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - run: ./ci/check-conventional-commits.sh "${{ github.event.pull_request.base.sha }}" "${{ github.event.pull_request.head.sha }}"

ci/check-conventional-commits.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [ $# -ne 2 ]; then
+  echo "Usage: $0 <base_ref> <head_ref>"
+  exit 1
+fi
+
+commits="$(git rev-list --reverse "^$1" "$2")"
+mapfile -t commits <<< "$commits"
+
+lf=$'\n'
+cr=$'\r'
+exclam='!'
+types="build|change|chore|ci|doc|feat|fix|perf|refactor|revert|style|test"
+regex="^($types)(\([^$lf$cr]+\))?$exclam?: .+\$"
+
+echo "Checking ${#commits[@]} commit(s)"
+for commit in "${commits[@]}"; do
+  echo "Checking commit $commit"
+  commit_msg="$(git log --format=%B -n 1 "$commit")"
+  if [[ ! "$commit_msg" =~ $regex ]]; then
+    echo "Commit $commit does not follow Conventional Commits format"
+    exit 1
+  fi
+done