Add project clusters API support

Add custom attributes to groups, users and projects apis

Fix ISOTime encoding in GET requests

Removes `url` struct tags from ContributionEvent and combines two checks
in one line.
Signed-off-by: Sune Keller <absukl@almbrand.dk>

Also implement the query.Encoder interface on ISOTime.
Signed-off-by: Sune Keller <absukl@almbrand.dk>

Event dates should be in the format YYYY-MM-DD

Fix the board list label field

It needs to be a single label, not a slice of labels.

Update service jira: fix JiraIssueTransitionID type from string to int

add missing group list options

Add support for protected tags

[Jobs] Pass job query string parameter to opt{} instead of static definition

Co-Authored-By: julienroland <roland.julien.perso@gmail.com>

[Jobs] Send job query parameter to opt{} instead of manually appending it to url path in download artifacts file

Added unit test

Added unit test for enviroments and added StopEnvironment function. did small change in issue_test.go

(jobs) support `pipeline` in jobs response

Ref: https://docs.gitlab.com/ce/api/jobs.html#get-a-single-job

Set request.GetBody to fix redirect issues

Gitlab uses the 307 status code to indicate a redirect. Since Go 1.8
that status code is supported by the HTTP package but it requires an
additional field (`GetBody`) to be set to enable resending the body.