🩹 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/.

.github/workflows/main.yml

@@ -15,9 +15,9 @@ jobs:
       # Needed to force UTF-8 and have consistent behavior in Windows
       PYTHONUTF8: 1
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@master
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@master
         with:
           python-version: ${{ matrix.python-version }}
       - name: Setup firefox ${{ matrix.firefox }}