Swap to Python 3.7 in Linux

Signed-off-by: Dan Yeaw <dan@yeaw.me>

.github/workflows/build.yml

@@ -36,7 +36,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v1
         with:
-          python-version: 3.8
+          python-version: 3.7
       - name: Install Ubuntu dependencies
         run: >
           sudo apt-get update -q && sudo apt-get install