docs: public Variable createPipelineScheduleVariable(Object projectIdOrPath, Integer pipelineScheduleId,
              String key, String value) throws GitLabApiException {
  
          GitLabApiForm formData = new GitLabApiForm()
                  .withParam("key", key, true)
                  .withParam("value", value, true);
          Response response = post(Response.Status.CREATED, formData,
                  "projects", getProjectIdOrPath(projectIdOrPath), "pipeline_schedules", pipelineScheduleId, "variables");
          return (response.readEntity(Variable.class));
      }