GitLabSourceAcl does not URL-encode the $filepath

[sverrehu]

See GitLab API doc: https://docs.gitlab.com/ee/api/#file-path-branches-and-tags-name-encoding

If a file path, branch or tag contains a /, make sure it is URL-encoded. For example, / is represented by %2F:

GET /api/v4/projects/1/repository/files/src%2FREADME.md?ref=master

GitLabSourceAcl.scala includes the $filepath from SOURCE_GITLAB_FILEPATH verbatim, leaving it to the person setting up Kafka Security Manager to know the API details of GitLab. I think the one doing the API call should handle the API requirements.

I do not speak Scala, so I cannot provide a patch. Sorry.