chore(gapic): update Python version in setup and mypy templates

Author: chalmerlowe

packages/gapic-generator/gapic/ads-templates/mypy.ini.j2

@@ -1,3 +1,3 @@
 [mypy]
-python_version = 3.8
+python_version = 3.10
 namespace_packages = True

packages/gapic-generator/gapic/ads-templates/setup.py.j2

@@ -64,7 +64,6 @@ setuptools.setup(
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
@@ -75,7 +74,7 @@ setuptools.setup(
     ],
     platforms="Posix; MacOS X; Windows",
     packages=packages,
-    python_requires=">=3.9",
+    python_requires=">=3.10",
     install_requires=dependencies,
     include_package_data=True,
     zip_safe=False,

packages/gapic-generator/gapic/templates/setup.py.j2

@@ -89,7 +89,6 @@ setuptools.setup(
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
@@ -100,7 +99,7 @@ setuptools.setup(
     ],
     platforms="Posix; MacOS X; Windows",
     packages=packages,
-    python_requires=">=3.9",
+    python_requires=">=3.10",
     install_requires=dependencies,
     extras_require=extras,
     include_package_data=True,