Don't try to run install tests under Python 3.5 since it's EOL and build

is now also failing with older version of Ubuntu runner.

Author: Kami

.github/workflows/install_test.yml

@@ -29,10 +29,8 @@ jobs:
           - "3.11"
           - "pypy-3.7"
         include:
-          # python 3.5 + 3.6 is not supported with ubuntu-latest anymore so we need to
+          # python 3.6 is not supported with ubuntu-latest anymore so we need to
           # use ubuntu 20.04
-          - python_version: 3.5
-            os: ubuntu-20.04
           - python_version: 3.6
             os: ubuntu-20.04