Update with pipeline schedule support

[lpiet]

Hopefully doing this the right way, but I figured if I open the issue I might contribute to the solution.

Tested it against our on premise gitlab instance and it seems to work. Hopefully should help implement the support for the pipeline schedules.

[gmessner]

@lpiet
The PR looks great. Just 3 small change requests:

1. Move the new pipeline schedule methods from ProjectApi to PipelineApi.

2. Create a pipeline-schedule.json file in src/test/resources/org/gitlab4j/api and add a test for it to src/test/java/org/gitlab4j/api/TestGitLabApiBeans.java. You'll find the JSON at: https://docs.gitlab.com/ee/api/pipeline_schedules.html#get-all-pipeline-schedules

3. Create src/test/java/org/gitlab4j/api/TestPipelineApi.java and move the pipeline schedule tests from TestProjectApi.java into it. I will add additional Pipeline API tests to this in the future.

[gmessner]

The pipeline schedule methods should be moved to the org.gitlab4j.api.PipelineApi class

[lpiet]

@gmessner,

I believe this covers it. I did notice that if I copy the exact json from the site any timestamp with a millisecond field of 000 fails the test (if it has any millisecond value it works) . But this was also the case for the existing tests.

The json converter strips the trailing 0's and then the generated and input json don't match.

ex. "next_run_at": "2017-05-19T13:41:00.000Z".

PS
I'll have one or two extra pull requests up next week, working through the functions I need for the role out at work and adding where needed.

[gmessner]

@lpiet
There are caveats when testing the JSON, this being one of them, I should have mentioned this, my apologies if you spent much time on this. The other big caveat is that values in the test file cannot have null as a value.

[gmessner]

@lpiet
I am assuming that you are done with this PR?

[lpiet]

correct

[gmessner]

@lpiet
This has been merged, A release will happen later this week. WIll let you know when the release is completed.

Thanks again for your contribution.