ci: python version to 3.9

Author: kozistr

.github/workflows/publish.yml

@@ -28,10 +28,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - name: Setup Python 3.10
+      - name: Setup Python 3.9
         uses: actions/setup-python@v2
         with:
-          python-version: 3.10
+          python-version: 3.9
       - name: Install dependencies
         run: python3 -m pip install -r requirements.txt
       - name: Publish package to PyPI