ci: don't test on deprecated python versions

Remove Python 3.7 and 3.8 from the CI test matrix, as these versions are
deprecated / EOL. This enables usage of Python 3.9+ features in scripts,
such as str.removeprefix/str.removesuffix, and should cause any issue since
the scripts are always executed manually anyways.

Signed-off-by: Mathieu Choplain <[email protected]>

.github/workflows/test.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10']
+        python-version: ['3.9', '3.10']
     steps:
       - uses: actions/checkout@v1
       - name: Set up Python