Update .github/workflows/ci.yml

Co-authored-by: Mitchell Borrego <mitchell@codecov.io>

Author: thomasrockhu-codecov

.github/workflows/ci.yml

@@ -6,6 +6,10 @@ jobs:
  steps:
  - name: Checkout
  uses: actions/checkout@v2
+ - name: Set up Python 3.9
+ uses: actions/setup-python@v2
+ with:
+ python-version: 3.9
  - name: Install dependencies
  run: pip install -r requirements.txt
  - name: Run tests and collect coverage