chore(deps): update dependency immutables to v0.16 (#267)

* chore(deps): update dependency immutables to v0.16

* 🦉 Updates from OwlBot

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

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

Author: renovate-bot

samples/snippets/noxfile.py

@@ -39,7 +39,7 @@
 
 TEST_CONFIG = {
     # You can opt out from the test for specific Python versions.
-    "ignored_versions": ["2.7"],
+    "ignored_versions": [],
     # Old samples are opted out of enforcing Python type hints
     # All new samples should feature them
     "enforce_type_hints": False,
@@ -86,15 +86,18 @@ def get_pytest_env_vars() -> Dict[str, str]:
 
 
 # DO NOT EDIT - automatically generated.
-# All versions used to tested samples.
-ALL_VERSIONS = ["2.7", "3.6", "3.7", "3.8", "3.9"]
+# All versions used to test samples.
+ALL_VERSIONS = ["3.6", "3.7", "3.8", "3.9"]
 
 # Any default versions that should be ignored.
 IGNORED_VERSIONS = TEST_CONFIG["ignored_versions"]
 
 TESTED_VERSIONS = sorted([v for v in ALL_VERSIONS if v not in IGNORED_VERSIONS])
 
-INSTALL_LIBRARY_FROM_SOURCE = bool(os.environ.get("INSTALL_LIBRARY_FROM_SOURCE", False))
+INSTALL_LIBRARY_FROM_SOURCE = os.environ.get("INSTALL_LIBRARY_FROM_SOURCE", False) in (
+    "True",
+    "true",
+)
 #
 # Style Checks
 #

samples/snippets/requirements.txt

@@ -25,7 +25,7 @@ googleapis-common-protos==1.53.0
 greenlet==1.1.0
 grpcio==1.39.0
 idna==3.2
-immutables==0.15
+immutables==0.16
 importlib-metadata==4.6.1
 libcst==0.3.19
 munch==2.5.0