chore(deps): update dependency google-api-python-client to v2.18.0 (#179)

Author: renovate-bot

language/snippets/api/requirements.txt

@@ -1,3 +1,3 @@
-google-api-python-client==2.15.0
+google-api-python-client==2.18.0
 google-auth==2.0.1
 google-auth-httplib2==0.1.0