remove reserved 'maintainers' field from package.json

this field is [used internally](https://docs.npmjs.com/files/package.json#people-fields-author-contributors) by npm; its presence may cause confusion

Author: boneskull

package.json

@@ -257,11 +257,6 @@
     "type": "git",
     "url": "git://github.com/mochajs/mocha.git"
   },
-  "maintainers": [
-    "travisjeffery <[email protected]>",
-    "jbnicolai <[email protected]>",
-    "boneskull <[email protected]>"
-  ],
   "main": "./index",
   "bin": {
     "mocha": "./bin/mocha",