resource/gitlab_topic: Add `title` argument support for GitLab 15.0
This change set adds support for the newly introduced title
field in GitLab 15.0 of the Topics API.
To support previous GitLab instances the title
resource attribute is optional even though in the API it's required.
However, it's an error if the user sets the title
for GitLab releases prior to 15.0 and if the user doesn't set it for GitLab releases from 15.0 on ...
Once we integrate 15.0 we have to adjust the tests, too to properly support the resource.
It's currently blocked by a new go-gitlab release we require.
Closes: #1043 (closed)