chore(python): Add kokoro configs for python 3.10 samples testing (#147)

Source-Link: googleapis/synthtool@c6e69c4
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:58f73ba196b5414782605236dd0712a73541b44ff2ff4d3a36ec41092dd6fa5b

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

scheduler/snippets/noxfile.py

@@ -87,7 +87,7 @@ def get_pytest_env_vars() -> Dict[str, str]:
 
 # DO NOT EDIT - automatically generated.
 # All versions used to test samples.
-ALL_VERSIONS = ["3.6", "3.7", "3.8", "3.9"]
+ALL_VERSIONS = ["3.6", "3.7", "3.8", "3.9", "3.10"]
 
 # Any default versions that should be ignored.
 IGNORED_VERSIONS = TEST_CONFIG["ignored_versions"]