Bump used gerrit API and hooks-its to version 2.8-SNAPSHOT
Bump used gerrit API and hooks-its to version 2.8-SNAPSHOT

Change-Id: I8fc2bfa643bf5b49a159af08f8fc8c4a38b3b773

GerritCodeReview/plugins_hooks-bugzilla,GerritCodeReview/plugins_its-phabricator,GerritCodeReview/plugins_its-phabricator