Require Python >=3.8 and add 3.11 to test matrix

Dropping 3.7 support was already announced in https://protobuf.dev/news/2023-07-06/ and meant to be dropped in
https://github.com/protocolbuffers/protobuf/pull/13219 but tests / setup.py were missed.

PiperOrigin-RevId: 567691335

.github/workflows/test_python.yml

@@ -17,7 +17,7 @@ jobs:
       fail-fast: false   # Don't cancel all jobs if one fails.
       matrix:
         type: [ Pure, C++]
-        version: [ "3.7", "3.8", "3.9", "3.10" ]
+        version: ["3.8", "3.9", "3.10", "3.11" ]
         include:
           - type: Pure
             targets: //python/... //upb/python/... //python:python_version_test
@@ -42,7 +42,7 @@ jobs:
       - name: Run tests
         uses: protocolbuffers/protobuf-ci/bazel-docker@v2
         with:
-          image: ${{ matrix.image || format('us-docker.pkg.dev/protobuf-build/containers/test/linux/python:{0}-66964dc8b07b6d1fc73a5cc14e59e84c1c534cea', matrix.version) }}
+          image: ${{ matrix.image || format('us-docker.pkg.dev/protobuf-build/containers/test/linux/python:{0}-63dd26c0c7a808d92673a3e52e848189d4ab0f17', matrix.version) }}
           credentials: ${{ secrets.GAR_SERVICE_ACCOUNT }}
           bazel-cache: python_linux/${{ matrix.type }}_${{ matrix.version }}
           bazel: test ${{ matrix.targets }} ${{ matrix.flags }} --test_env=KOKORO_PYTHON_VERSION
@@ -54,7 +54,7 @@ jobs:
       matrix:
         type: [ Pure, C++]
         # TODO Consider expanding this set of versions.
-        version: [ "3.10" ]
+        version: [ "3.11" ]
         include:
           - type: Pure
             targets: //python/... //upb/python/... //python:python_version_test

python/setup.py

@@ -425,13 +425,13 @@ if __name__ == '__main__':
       classifiers=[
           'Programming Language :: Python',
           'Programming Language :: Python :: 3',
-          'Programming Language :: Python :: 3.7',
           # LINT.IfChange
           # Remove importlib fallback path when we drop Python 3.8 support.
           'Programming Language :: Python :: 3.8',
           # LINT.ThenChange(//depot/google3/google/protobuf/internal/test_util.py)
           'Programming Language :: Python :: 3.9',
           'Programming Language :: Python :: 3.10',
+          'Programming Language :: Python :: 3.11',
       ],
       namespace_packages=['google'],
       packages=find_packages(
@@ -449,5 +449,5 @@ if __name__ == '__main__':
       },
       install_requires=install_requires,
       ext_modules=ext_module_list,
-      python_requires='>=3.7',
+      python_requires='>=3.8',
   )