Update test_prs.yml

Author: ZoranPandovski

.github/workflows/test_prs.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: [3.7,3.8,3.9]
+        python-version: [3.8,3.9]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}