Update JSDoc return type description in mailauth.js (#107)

Author: SpeedyCraftah

lib/mailauth.js

@@ -30,7 +30,7 @@ const { isIP } = require('net');
  * @param {Boolean} [opts.disableArc=false] If true then do not perform ARC validation and sealing
  * @param {Boolean} [opts.disableDmarc=false] If true then do not perform DMARC check
  * @param {Boolean} [opts.disableBimi=false] If true then do not perform BIMI check
- * @returns {Object} Authentication result
+ * @returns Authentication result
  */
 const authenticate = async (input, opts) => {
     opts = Object.assign({}, opts); // copy keys