deps: update google.core.version to v2.3.5 (#565)
deps: update google.core.version to v2.3.5 (#565)

deps: update dependency com.google.api:api-common to v2.1.2
deps: update gax.version to v2.8.1 
googleapis/java-shared-dependencies,googleapis/java-shared-dependencies,googleapis/java-shared-dependencies