feat(gitlab): add support for GitLab protected branches (list and unprotect)

ts/gitlab.interfaces.ts

@@ -44,6 +44,12 @@ export interface IVariableOptions {
   environment_scope?: string;
 }
 
+export interface IGitLabProtectedBranch {
+  id: number;
+  name: string;
+  allow_force_push: boolean;
+}
+
 export interface IGitLabPipeline {
   id: number;
   project_id: number;