Test with multiple pythons

Author: nothingface0

.github/workflows/build_installation_package.yaml

@@ -4,7 +4,7 @@ on: [push]
 
 jobs:
   build_and_upload:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         python-version: ["3.6", "3.8"]