Use Gitlab::PushOptions for `ci.skip` push option

Previously the raw push option Array was sent to Pipeline::Chain::Skip.

This commit updates this class (and the chain of classes that pass the
push option parameters from the API internal `post_receive` endpoint to
that class) to treat push options as a Hash of options parsed by
GitLab::PushOptions.

The GitLab::PushOptions class takes options like this:

    -o ci.skip -o merge_request.create -o merge_request.target=branch

and turns them into a Hash like this:

    {
      ci: {
        skip: true
      },
      merge_request: {
        create: true,
        target: 'branch'
      }
    }

This now how Pipeline::Chain::Skip is determining if the `ci.skip` push
option was used.

1 files changed, 12 insertions, 0 deletions

diff --git a/spec/lib/gitlab/push_options_spec.rb b/spec/lib/gitlab/push_options_spec.rb
index 68b64863c21..fc9e421bea6 100644
--- a/spec/lib/gitlab/push_options_spec.rb
+++ b/spec/lib/gitlab/push_options_spec.rb
@@ -39,6 +39,18 @@ describe Gitlab::PushOptions do
     end
   end
 
+  describe '#as_json' do
+    it 'returns all options' do
+      options = described_class.new(['merge_request.target=value'])
+
+      expect(options.as_json).to include(
+        merge_request: {
+          target: 'value'
+        }
+      )
+    end
+  end
+
   it 'can parse multiple push options' do
     options = described_class.new([
       'merge_request.create',