chore: drop Python 3.9 support (EOL October 2025)

Remove 3.9 from CI matrix, classifiers, requires-python, and ruff
target-version. Minimum supported version is now Python 3.10.

Author: constantinius

.github/workflows/main.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-24.04
     strategy:
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+        python-version: ['3.10', '3.11', '3.12', '3.13']
     steps:
     - uses: actions/checkout@v4
     - uses: actions/setup-python@v5

pyproject.toml

@@ -7,15 +7,14 @@ name = "pygeofilter"
 description = "pygeofilter is a pure Python parser implementation of OGC filtering standards"
 readme = "README.md"
 license = "MIT"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 authors = [
     { name = "Fabian Schindler", email = "fabian.schindler@eox.at" },
 ]
 classifiers = [
     "Development Status :: 3 - Alpha",
     "Intended Audience :: Developers",
     "Topic :: Scientific/Engineering :: GIS",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
@@ -87,7 +86,7 @@ include = ["pygeofilter*"]
 pygeofilter = ["py.typed", "**/*.lark"]
 
 [tool.ruff]
-target-version = "py39"
+target-version = "py310"
 line-length = 80
 
 [tool.ruff.lint]