Use python from brew

.github/workflows/main.yml

@@ -14,10 +14,6 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
-      - name: Set up Python 3
-        uses: actions/setup-python@v2
-        with:
-          python-version: "3.6"
       - name: Install Python Dependencies
         run: |
           python3 -m pip install -U pip