lib/plugins/aws/provider/awsProvider.js/AwsProvider/getMethodArn
class AwsProvider:  getMethodArn(accountId, apiId, method, pathParam) {
    const region = this.getRegion();
    let path = pathParam;
    if (pathParam.startsWith('/')) {
      path = pathParam.replace(/^\/+/g, '');
    }
    return `arn:aws:execute-api:${region}:${accountId}:${apiId}/*/${method.toUpperCase()}/${path}`;
  }