remove Python 3.4 from CI as it's no longer available

Author: Technologicat

.github/workflows/python-package.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.4, 3.5, 3.6, 3.7, "pypy3"]
+        python-version: [3.5, 3.6, 3.7, "pypy3"]
 
     steps:
     - uses: actions/checkout@v2