Support `/client/features` Unleash endpoint
What does this MR do?
This adds support for /client/features
required by all v3
client libraries of Unleash.
What are the relevant issue numbers?
Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/8119
Does this MR meet the acceptance criteria?
-
Changelog entry added, if necessary -
Tests added for this feature/bug -
Conforms to the code review guidelines -
Conforms to the style guides
Edited by Kamil Trzciński