feat: drop python 3.9 and update deps

Author: eggplants

pyproject.toml

@@ -14,12 +14,11 @@ keywords = [
 ]
 license = { text = "APACHE 2.0" }
 authors = [ { name = "OpenAPI Generator community", email = "[email protected]" } ]
-requires-python = ">=3.9,<4"
+requires-python = ">=3.10,<4"
 classifiers = [
   "License :: OSI Approved :: Apache Software License",
   "Programming Language :: Python",
   "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",