ci: use `package.json` version of prettier

.github/workflows/prettier.yml

@@ -11,13 +11,11 @@ jobs:
     steps:
       - name: Check out repo
         uses: actions/checkout@v3
-      - uses: actions/cache@v3
-        name: Configure npm caching
+      - uses: actions/setup-node@v3
         with:
-          path: ~/.npm
-          key: ${{ runner.os }}-npm-${{ hashFiles('**/workflows/prettier.yml') }}
-          restore-keys: |
-            ${{ runner.os }}-npm-
+          node-version: 16
+          cache: "npm"
+      - run: npm ci
       - name: Run prettier
         run: |-
-          npx prettier --check .
+          npm run format:check

package.json

@@ -159,6 +159,7 @@
 		"test:watch": "jest --watch",
 		"coverage": "jest --coverage --collectCoverageFrom=\"./lib/**\"",
 		"format": "prettier --write .",
+		"format:check": "prettier --check .",
 		"semantic-release": "semantic-release",
 		"e2e": "wdio run e2e/wdio.local.conf.ts",
 		"e2e:bstack": "wdio run e2e/wdio.bstack.conf.ts"