checkEngineWarning(pckJSON) {
    const scEngine = pckJSON.engines?.saltcorn;
    if (
      this.scVersion &&
      scEngine &&
      !semver.satisfies(this.scVersion, scEngine)
    ) {
      const warnMsg = `Plugin ${this.plugin.name} requires Saltcorn version ${scEngine} but running ${this.scVersion}`;
      getState().log(4, warnMsg);
      return warnMsg;
    }
    return null;
  }
check if the host supports the plugin and return a warning if not
@param pckJSON
@returns