chore: install and configure commitlint

CONTRIBUTING.md

@@ -6,6 +6,10 @@
 * `cd ember-amount-input`
 * `pnpm install`
 
+## Conventional Commits
+
+This repository enforces conventional commits through Git hooks and `commitlint`. Thus, your commits must follow the [Conventional Commits spec](https://www.conventionalcommits.org/en/v1.0.0/) and `@commitlint/config-conventional` [rules](https://github.com/conventional-changelog/commitlint/tree/master/%40commitlint/config-conventional#rules).
+
 ## Linting
 
 * `pnpm lint`

commitlint.config.js

@@ -0,0 +1,9 @@
+"use strict";
+
+module.exports = {
+  extends: ["@commitlint/config-conventional"],
+  rules: {
+    "body-leading-blank": [2, "always"],
+    "footer-leading-blank": [2, "always"],
+  },
+};

lefthook.yml

@@ -0,0 +1,4 @@
+commit-msg:
+  commands:
+    commitlint:
+      run: pnpm commitlint --edit $1

package.json

@@ -13,16 +13,20 @@
     "lint": "pnpm --filter '*' lint",
     "lint:fix": "pnpm --filter '*' lint:fix",
     "lint:types": "pnpm --filter '*' lint:types",
+    "postinstall": "lefthook install",
     "prepare": "pnpm build",
     "start": "concurrently 'pnpm:start:*' --restart-after 5000 --prefix-colors cyan,white,yellow",
     "start:addon": "pnpm --filter ember-amount-input start",
     "start:test-app": "pnpm --filter test-app start",
     "test": "pnpm --filter '*' test"
   },
   "devDependencies": {
+    "@commitlint/cli": "^18.4.3",
+    "@commitlint/config-conventional": "^18.4.3",
     "@release-it-plugins/lerna-changelog": "^6.0.0",
     "@release-it-plugins/workspaces": "^4.0.0",
     "concurrently": "^8.2.2",
+    "lefthook": "^1.5.5",
     "prettier": "^3.1.0",
     "release-it": "^16.2.1"
   },