remove python 3.5 from GitHub test workflow

Author: digorgonzola

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [ '3.5', '3.8' ]
+        python-version: [ '3.8' ]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}