feat: add support for Python 3.10 (#615)

Co-authored-by: Anthonios Partheniou <partheniou@google.com>

CONTRIBUTING.rst

@@ -22,7 +22,7 @@ In order to add a feature:
   documentation.
 
 - The feature must work fully on the following CPython versions:  2.7,
-  3.5, 3.6, 3.7 and 3.8 on both UNIX and Windows.
+  3.5, 3.6, 3.7, 3.8, 3.9 and 3.10 on both UNIX and Windows.
 
 - The feature must not add unnecessary dependencies (where
   "unnecessary" is of course subjective, but new dependencies should
@@ -111,7 +111,7 @@ Coding Style
   should point to the official ``googleapis`` checkout and the
   the branch should be the main branch on that remote (``main``).
 
-- This repository contains configuration for the 
+- This repository contains configuration for the
   `pre-commit <https://pre-commit.com/>`__ tool, which automates checking
   our linters during a commit.  If you have it installed on your ``$PATH``,
   you can enable enforcing those checks via:
@@ -156,7 +156,7 @@ Running System Tests
     `docs <https://cloud.google.com/storage/docs/authentication#generating-a-private-key>`__
     for more details.
 
-- Once you have downloaded your json keys, set the environment variable 
+- Once you have downloaded your json keys, set the environment variable
   ``GOOGLE_APPLICATION_CREDENTIALS`` to the absolute path of the json file::
 
    $ export GOOGLE_APPLICATION_CREDENTIALS="/Users/<your_username>/path/to/app_credentials.json"

noxfile.py

@@ -29,7 +29,7 @@
 
 DEFAULT_PYTHON_VERSION = "3.8"
 SYSTEM_TEST_PYTHON_VERSIONS = ["2.7", "3.8"]
-UNIT_TEST_PYTHON_VERSIONS = ["2.7", "3.6", "3.7", "3.8", "3.9"]
+UNIT_TEST_PYTHON_VERSIONS = ["2.7", "3.6", "3.7", "3.8", "3.9", "3.10"]
 CONFORMANCE_TEST_PYTHON_VERSIONS = ["3.8"]
 
 _DEFAULT_STORAGE_HOST = "https://storage.googleapis.com"

owlbot.py

@@ -26,6 +26,7 @@
 templated_files = common.py_library(
     cov_level=100,
     split_system_tests=True,
+    unit_test_python_versions=["3.6", "3.7", "3.8", "3.9", "3.10"],
     system_test_external_dependencies=[
         "google-cloud-iam",
         "google-cloud-pubsub < 2.0.0",

setup.py

@@ -91,6 +91,7 @@
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
         "Operating System :: OS Independent",
         "Topic :: Internet",
     ],