chore: drop support for PY3.9 since it reached EOL

Signed-off-by: Tudor Plugaru <[email protected]>

Author: PlugaruT

.github/workflows/main.yml

@@ -1,9 +1,8 @@
 name: CI
 
-on: [ push, pull_request ]
+on: [push, pull_request]
 
 jobs:
-
   lint:
     runs-on: ubuntu-latest
     steps:
@@ -23,8 +22,8 @@ jobs:
   test:
     strategy:
       matrix:
-        python-version: [ '3.9', '3.10', '3.11', '3.12' ]
-        os: [ ubuntu-latest, windows-latest, macos-latest ]
+        python-version: ["3.10", "3.11", "3.12"]
+        os: [ubuntu-latest, windows-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4

pyproject.toml

@@ -6,7 +6,7 @@ authors = [
     { name = "The Cloud Events Contributors", email = "[email protected]" }
 ]
 readme = "README.md"
-requires-python = ">= 3.9"
+requires-python = ">= 3.10"
 license = "Apache-2.0"
 classifiers = [
     "Intended Audience :: Information Technology",
@@ -19,7 +19,6 @@ classifiers = [
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3 :: Only",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
@@ -81,7 +80,7 @@ packages = ["src/cloudevents"]
 
 [tool.ruff]
 line-length = 88
-target-version = "py39"
+target-version = "py310"
 
 exclude = [
     ".bzr",
@@ -122,7 +121,7 @@ testpaths = [
 ]
 
 [tool.mypy]
-python_version = 3.9
+python_version = "3.10"
 
 ignore_missing_imports = true
 namespace_packages = true