Autogenerated update (2018-01-30)

Update:
- appengine_v1
- appengine_v1beta
- bigquerydatatransfer_v1
- cloudbuild_v1
- drive_v2
- sheets_v4

generated/google/apis/drive_v2/classes.rb

@@ -2423,7 +2423,8 @@ module Google
         # - They can only be set on user and group permissions
         # - The date must be in the future
         # - The date cannot be more than a year in the future
-        # - The date can only be set on drive.permissions.update requests
+        # - The date can only be set on drive.permissions.update or drive.permissions.
+        # patch requests
         # Corresponds to the JSON property `expirationDate`
         # @return [DateTime]
         attr_accessor :expiration_date