Remove sstcheck from tests

.github/workflows/python-tests.yml

@@ -32,9 +32,6 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-    - name: Check README.rst syntax
-      run: |
-        rstcheck --report warning README.rst
     - name: Test building documentation
       run: |
         cd docs