Update CI and docs for Python up to py311

.github/workflows/python-package.yml

@@ -8,6 +8,9 @@ on:
     branches: '**'
   pull_request:
     branches: '**'
+  schedule:
+    # 3 am Tuesdays and Fridays
+    - cron: "0 3 * * 2,5"
 
 jobs:
   build:
@@ -15,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: [3.6, 3.7, 3.8, 3.9, "3.10", "3.11"]
 
     steps:
     - uses: actions/checkout@v2
@@ -26,9 +29,9 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip setuptools wheel
-        pip install flake8 pytest
-        pip install coverage
-        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+        python -m pip install flake8 pytest
+        python -m pip install coverage
+        if [ -f requirements.txt ]; then python -m pip install -r requirements.txt; fi
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names