/**
 * Returns the Gravatar URL of a given email id.
 *
 * @param {string} key - Email or id for which we need gravatar URL.
 * @param {string} [baseURL='https://www.gravatar.com/avatar/'] - Base Gravatar URL.
 * @returns {string} Gravatar URL.
 */
export declare function getGravatarURL(key: string, baseURL?: string): string;