chore: drop contributors from multiple places (#262)

Author: JustinBeckwith

.mailmap

@@ -28,31 +28,6 @@
     "vision",
     "Google Cloud Vision API"
   ],
-  "contributors": [
-    "Ace Nassri <anassri@google.com>",
-    "Alexander Fenster <fenster@google.com>",
-    "Ali Ijaz Sheikh <ofrobots@google.com>",
-    "Christopher Wilcox <git@crwilcox.com>",
-    "Dave Gramlich <callmehiphop@gmail.com>",
-    "Ernest Landrito <landrito@google.com>",
-    "Gus Class <gguuss@gmail.com>",
-    "Jason Dobry <jdobry@google.com>",
-    "Jonathan Lui <kinwa91@msn.com>",
-    "Jun Mukai <mukai@google.com>",
-    "Justin Beckwith <beckwith@google.com>",
-    "Justin Beckwith <justin.beckwith@gmail.com>",
-    "Kelvin Jin <kelvinjin@google.com>",
-    "Luke Sneeringer <lukesneeringer@google.com>",
-    "Rebecca Taylor <remily@google.com>",
-    "Shahin <happyhuman@users.noreply.github.com>",
-    "Song Wang <songwang@google.com>",
-    "Stephen Sawchuk <sawchuk@gmail.com>",
-    "Tim Swast <swast@google.com>",
-    "calibr <awcalibr@gmail.com>",
-    "dpebot <dpebot@google.com>",
-    "greenkeeper[bot] <greenkeeper[bot]@users.noreply.github.com>",
-    "rtw <rtw1981@gmail.com>"
-  ],
   "scripts": {
     "cover": "nyc --reporter=lcov mocha test/*.js && nyc report",
     "docs": "jsdoc -c .jsdoc.js",