Bumped versions in Github actions configuration to v3.

Author: felixxm

.github/workflows/test.yml

@@ -10,9 +10,9 @@ jobs:
         python-version: [3.6, 3.7, 3.8, 3.9]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install tox