Update hook project wiki event wqattribute to wiki_page_events
Update hook project wiki event wqattribute to wiki_page_events

In GitLab 11.11, the Project Hook Key for wiki events was wiki_events.
We don't support GitLab 11.X. We only support GitLab 12.9.2+.
In new version of GitLab the correct key is wiki_page_events.

gmessner/gitlab4j-api