chore(gapic): update Python version requirement to 3.10 in setup.py and noxfile.py

Author: chalmerlowe

packages/gapic-generator/noxfile.py

@@ -44,7 +44,6 @@
 RUFF_EXCLUDES = "*golden*,*pb2.py,*pb2.pyi"
 
 ALL_PYTHON = (
-    "3.9",
     "3.10",
     "3.11",
     "3.12",
@@ -181,7 +180,7 @@ def fragment(session, use_ads_templates=False):
     session.install("-e", ".")
 
     # The specific failure is `Plugin output is unparseable`
-    if session.python in ("3.9", "3.10"):
+    if session.python == "3.10":
         session.install("google-api-core<2.28")
 
     frag_files = (
@@ -251,7 +250,7 @@ def showcase_library(
     # Warnings emitted from google-api-core starting in 2.28
     # appear to cause issues when running protoc.
     # The specific failure is `Plugin output is unparseable`
-    if session.python in ("3.9", "3.10"):
+    if session.python == "3.10":
         session.install("google-api-core<2.28")
 
     # Install a client library for Showcase.

packages/gapic-generator/setup.py

@@ -70,7 +70,6 @@
         "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",
@@ -81,7 +80,7 @@
         "Topic :: Software Development :: Libraries :: Python Modules",
     ],
     platforms="Posix; MacOS X",
-    python_requires=">=3.9",
+    python_requires=">=3.10",
     install_requires=dependencies,
     include_package_data=True,
     zip_safe=False,