Drop support for Python <=3.9

Author: hartwork

.github/workflows/run-tests.yml

@@ -19,7 +19,7 @@ jobs:
     name: Run the test suite
     strategy:
       matrix:
-        python-version: [3.9, 3.13]  # no particular need for in-between versions
+        python-version: ["3.10", 3.13]  # no particular need for in-between versions
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8  # v5.0.0

ruff.toml

@@ -1,6 +1,6 @@
 indent-width = 4
 line-length = 99
-target-version = "py39"
+target-version = "py310"
 
 [lint]
 select = [