build: github action typo

Author: weakish

.github/workflows/pythonpackage.yml

@@ -43,13 +43,13 @@ jobs:
     strategy:
       max-parallel: 1
       matrix:
-        python-version: [ '2.7', '3.5', '3.6', '3.7', '3.8', '3.9']
+        python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python 
       uses: actions/setup-python@v2
       with:
-        ${{ matrix.python-version }}
+        python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip