Added changes field in push event struct for Bitbucket server

added changes field in push event struct for Bitbucket to
make it available in PipelineRun's dynamic variable

https://issues.redhat.com/browse/SRVKP-6981

Signed-off-by: Zaki Shaikh <zashaikh@redhat.com>

pkg/provider/bitbucketserver/types/types.go

@@ -23,13 +23,29 @@ type PullRequestEvent struct {
 }
 
 type PushRequestEventChange struct {
-	ToHash string `json:"toHash"`
-	RefID  string `json:"refId"`
+	Ref      Ref    `json:"ref"`
+	FromHash string `json:"fromHash"`
+	ToHash   string `json:"toHash"`
+	RefID    string `json:"refId"`
+	Type     string `json:"type"`
+}
+
+type Ref struct {
+	ID        string `json:"id"`
+	DisplayID string `json:"displayId"`
+	Type      string `json:"type"`
 }
 
 type PushRequestEvent struct {
+	EventKey   string                   `json:"eventKey"`
 	Actor      bbv1.UserWithLinks       `json:"actor"`
 	Repository bbv1.Repository          `json:"repository"`
 	Changes    []PushRequestEventChange `json:"changes"`
 	Commits    []bbv1.Commit            `json:"commits"`
+	ToCommit   ToCommit                 `json:"toCommit"`
+}
+
+type ToCommit struct {
+	bbv1.Commit
+	Parents []bbv1.Commit `json:"parents"` // bbv1.Commit also has Parents field, but its Parents has only two fields while actual payload has more.
 }