Work around Gitlab issue #21468 (#74)

https://gitlab.com/gitlab-org/gitlab-ce/issues/21468

events.go

@@ -16,8 +16,6 @@
 
 package gitlab
 
-import "time"
-
 // PushEvent represents a push event.
 //
 // GitLab API docs:
@@ -74,8 +72,8 @@ type IssueEvent struct {
 		AssigneeID  int    `json:"assignee_id"`
 		AuthorID    int    `json:"author_id"`
 		ProjectID   int    `json:"project_id"`
-		CreatedAt   *time.Time `json:"created_at"`
-		UpdatedAt   *time.Time `json:"updated_at"`
+		CreatedAt   string `json:"created_at"` // Should be *time.Time (see Gitlab issue #21468)
+		UpdatedAt   string `json:"updated_at"` // Should be *time.Time (see Gitlab issue #21468)
 		Position    int    `json:"position"`
 		BranchName  string `json:"branch_name"`
 		Description string `json:"description"`
@@ -231,8 +229,8 @@ type MergeEvent struct {
 		AuthorID        int         `json:"author_id"`
 		AssigneeID      int         `json:"assignee_id"`
 		Title           string      `json:"title"`
-		CreatedAt       *time.Time  `json:"created_at"`
-		UpdatedAt       *time.Time  `json:"updated_at"`
+		CreatedAt       string      `json:"created_at"` // Should be *time.Time (see Gitlab issue #21468)
+		UpdatedAt       string      `json:"updated_at"` // Should be *time.Time (see Gitlab issue #21468)
 		StCommits       []*Commit   `json:"st_commits"`
 		StDiffs         []*Diff     `json:"st_diffs"`
 		MilestoneID     int         `json:"milestone_id"`