deps!: drop Python 3.9 support to allow urllib3 >=2.7.0 (#227)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: 3 people

.github/workflows/pytest.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       max-parallel: 5
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+        python-version: ['3.10', '3.11', '3.12', '3.13']
 
     steps:
       - name: Cloning repo