Rollback docker image to fix CI
As discussed in https://gitlab.com/gitlab-org/gitter/webapp/-/merge_requests/1788#note_299161132
The image was updated in https://gitlab.com/gitlab-org/gitter/webapp/-/merge_requests/1787 but the Docker builds were failing
This MR rolls back to the previous image to fix the build then we'll keep working on updating the image in !1788 (merged)
Edited by Eric Eastwood