fix!: drop python 3.9 support

BREAKING CHANGE: drop support for Python 3.9

Author: wyardley

.github/workflows/linting.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+        python-version: ['3.10', '3.11', '3.12', '3.13']
     name: Python ${{ matrix.python-version }}
 
     steps:

.github/workflows/main.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+        python-version: ['3.10', '3.11', '3.12', '3.13']
     name: Python ${{ matrix.python-version }}
 
     steps:

.github/workflows/windows.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: windows-latest
     strategy:
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+        python-version: ['3.10', '3.11', '3.12', '3.13']
     name: Python ${{ matrix.python-version }} (Windows)
 
     steps: