🩹 fix deprecation warning:

   Node.js 12 actions are deprecated.
   For more information see:
   https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/.
   Please update the following actions to use Node.js 16: actions/checkout@v2

   Using version v3, latest or master: actions/checkout#689

.github/workflows/ci.yml

@@ -11,9 +11,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@master
       - name: Use Node.js 12
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@master
         with:
           node-version: '12.x'
       - run: npm ci