chore: revert python version changes in workflows

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: [3.9]
+        python-version: [3.8, 3.9]
     steps:
     - uses: actions/checkout@v2
     - name: setup python
@@ -41,7 +41,7 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@v2
       with:
-        python-version: 3.9
+        python-version: 3.8
     - name: Install pip, setuptools, and wheel
       run: pip install -r requirements/pip.txt
     - name: Install dependencies
@@ -58,7 +58,7 @@ jobs:
     - name: Setup Python
       uses: actions/setup-python@v2
       with:
-        python-version: 3.9
+        python-version: 3.8
     - name: Install pip, setuptools, and wheel
       run: pip install -r requirements/pip.txt
     - name: Install dependencies

docs/conf.py

@@ -63,7 +63,6 @@ def get_version(*file_paths):
 # ones.
 extensions = [
     'sphinx_book_theme',
-    'pydata_sphinx_theme',
     'sphinx.ext.autodoc',
     'sphinx.ext.doctest',
     'sphinx.ext.intersphinx',

tox.ini

@@ -3,8 +3,8 @@ envlist = py{38,39}
 
 [gh-actions]
 python =
-    3.9: py39, docs, quality
-
+    3.8: py38, docs, quality
+    3.9: py39
 [doc8]
 max-line-length = 120