Update branch API endpoint to show effective branch protection. (#9031)

* Add API endpoint for displaying effective branch protection.

* Add status checks.

modules/structs/repo_branch.go

@@ -6,6 +6,12 @@ package structs
 
 // Branch represents a repository branch
 type Branch struct {
-	Name   string         `json:"name"`
-	Commit *PayloadCommit `json:"commit"`
+	Name                string         `json:"name"`
+	Commit              *PayloadCommit `json:"commit"`
+	Protected           bool           `json:"protected"`
+	RequiredApprovals   int64          `json:"required_approvals"`
+	EnableStatusCheck   bool           `json:"enable_status_check"`
+	StatusCheckContexts []string       `json:"status_check_contexts"`
+	UserCanPush         bool           `json:"user_can_push"`
+	UserCanMerge        bool           `json:"user_can_merge"`
 }