Bump minimum Python version from 3.9 to 3.10

Python 3.9 reached end-of-life in October 2025. This change:
- Updates requires-python to >=3.10
- Removes Python 3.9 from CI test matrix
- Removes MySQL 5.7 test (was only run with Python 3.9)

Author: claude

.github/workflows/test.yaml

@@ -21,11 +21,8 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        py_ver: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        py_ver: ["3.10", "3.11", "3.12", "3.13"]
         mysql_ver: ["8.0"]
-        include:
-          - py_ver: "3.9"
-            mysql_ver: "5.7"
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python ${{matrix.py_ver}}

pyproject.toml

@@ -22,7 +22,7 @@ dependencies = [
   "urllib3",
   "setuptools",
 ]
-requires-python = ">=3.9,<4.0"
+requires-python = ">=3.10,<4.0"
 authors = [
   {name = "Dimitri Yatsenko", email = "[email protected]"},
   {name = "Thinh Nguyen", email = "[email protected]"},