code: public void deleteBranch(Object projectIdOrPath, String branchName) throws GitLabApiException {
          Response.Status expectedStatus = (isApiVersion(ApiVersion.V3) ? Response.Status.OK : Response.Status.NO_CONTENT);
          delete(expectedStatus, null, "projects",
                  getProjectIdOrPath(projectIdOrPath), "repository", "branches", urlEncode(branchName));
      }
docs: Delete a single project repository branch.
  
  <pre><code>GitLab Endpoint: DELETE /projects/:id/repository/branches/:branch</code></pre>
  
  @param projectIdOrPath the project in the form of an Integer(ID), String(path), or Project instance
  @param branchName the name of the branch to delete
  @throws GitLabApiException if any exception occurs