fix(endpoints): update sample deployment apiVersion to apps/v1 (#2157)
fix(endpoints): update sample deployment apiVersion to apps/v1 (#2157)

Deprecated APIs was removed from 1.16.

Similar changes made in #1893 need to be applied to this sample.
GoogleCloudPlatform/golang-samples,GoogleCloudPlatform/golang-samples,GoogleCloudPlatform/golang-samples