code: async function _searchCiConfig (searchString) {
    const ciConfigs = await Promise.all(['.travis.yml', 'appveyor.yml'].map(async (filename) => {
      try {
        return await fs.readFile(filename, 'utf-8')
      } catch (e) {
        if (e.code === 'ENOENT') {
          return ''
        }
        /* istanbul ignore next */
        throw e
      }
    }))
    return ciConfigs.findIndex((contents) => contents.includes(searchString)) >= 0
  }
docs: Internal function to look for a given string in popular CI config files (like .travis.yml and appveyor.yml)
  @param {string} searchString the string to search for within the ci files
  @return {Promise<boolean>} true, if the given string is either part of .travis.yml or appveyor.yml
  @private