remove 3.9 from python packaging action

.github/workflows/python-package.yml

@@ -1,6 +1,8 @@
 # This workflow will install Python dependencies, run tests and lint with a variety of Python versions
 # For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-python
 
+# [ ] TODO [pep 458](https://blog.pypi.org/posts/2024-11-14-pypi-now-supports-digital-attestations/)
+
 name: Python package
 
 on:
@@ -16,7 +18,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.10", "3.11", "3.12"]
 
     steps:
     - uses: actions/checkout@v4