chore: add draft to gitlab merge-request-event payload

updated the structs based on https://docs.gitlab.com/ee/user/project/integrations/webhook_events.html#merge-request-events

gitlab/payload.go

@@ -724,6 +724,7 @@ type ObjectAttributes struct {
 	NoteableID       int64      `json:"noteable_id"` // nolint: misspell
 	System           bool       `json:"system"`
 	WorkInProgress   bool       `json:"work_in_progress"`
+	Draft            bool       `json:"draft"`
 	StDiffs          []StDiff   `json:"st_diffs"`
 	Source           Source     `json:"source"`
 	Target           Target     `json:"target"`
@@ -880,14 +881,21 @@ type Author struct {
 // Changes contains all changes associated with a GitLab issue or MR
 type Changes struct {
 	LabelChanges LabelChanges `json:"labels"`
+	DraftChanges DraftChanges `json:"drafts"`
 }
 
-// LabelChanges contains changes in labels assocatiated with a GitLab issue or MR
+// LabelChanges contains changes in labels associated with a GitLab issue or MR
 type LabelChanges struct {
 	Previous []Label `json:"previous"`
 	Current  []Label `json:"current"`
 }
 
+// DraftChanges contains the current and previous value of the draft property, tells us if draft was toggles
+type DraftChanges struct {
+	Previous bool `json:"previous"`
+	Current  bool `json:"current"`
+}
+
 // Label contains all of the GitLab label information
 type Label struct {
 	ID          int64      `json:"id"`

testdata/gitlab/merge-request-event.json

@@ -52,6 +52,7 @@
     "state": "opened",
     "blocking_discussions_resolved": true,
     "work_in_progress": false,
+    "draft": false,
     "first_contribution": true,
     "merge_status": "unchecked",
     "target_project_id": 14,
@@ -137,6 +138,10 @@
       "previous": null,
       "current": 1
     },
+    "draft": {
+      "previous": true,
+      "current": false
+    },
     "updated_at": {
       "previous": "2017-09-15 16:50:55 UTC",
       "current":"2017-09-15 16:52:00 UTC"
@@ -192,4 +197,4 @@
       "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=40\u0026d=identicon"
     }
   ]
-}
+}