another attempt to remove python 3.7

Author: kaseylove

.github/workflows/build_docs.yml

@@ -14,7 +14,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v2
       with:
-        python-version: 3.7
+        python-version: 3.8
     - name: Install Python dependencies
       run: pip install -e .[dev]
     - name: Build documentation and deploy