Bump Python version for docs

Author: domdfcoding

.github/workflows/docs_test_action.yml

@@ -29,7 +29,7 @@ jobs:
               - '!tests/**'
 
       - name: Install and Build 🔧
-        uses: sphinx-toolbox/sphinx-action@sphinx-3.3.1
+        uses: sphinx-toolbox/sphinx-action@sphinx-3.3.1-py39
         if: steps.changes.outputs.code == 'true'
         with:
           pre-build-command: python -m pip install tox

repo_helper.yml

@@ -15,7 +15,6 @@ use_whey: true
 min_coverage: 100
 preserve_custom_theme: true
 mypy_version: 1.16
-python_deploy_version: 3.9
 
 conda_channels:
   - conda-forge

tox.ini

@@ -65,7 +65,7 @@ setenv =
 [testenv:docs]
 setenv = SHOW_TODOS = 1
 passenv = SPHINX_BUILDER
-basepython = python3.8
+basepython = python3.9
 changedir = {toxinidir}/doc-source
 deps = -r{toxinidir}/doc-source/requirements.txt
 commands = sphinx-build -M {env:SPHINX_BUILDER:html} . ./build {posargs}