Revert "Merge pull request #205 from websharik/main"

This reverts commit e284ef51ee54def132acbbd96202c51b11d70b67, reversing
changes made to 40db78ea7d93e00d35001d1bd0c6c515b077df2c.

src/managers/MessageManager.js

@@ -1,6 +1,7 @@
 'use strict';
 
 const { Collection } = require('@discordjs/collection');
+const BigNumber = require('bignumber.js');
 const CachedManager = require('./CachedManager');
 const { TypeError, Error } = require('../errors');
 const { Message } = require('../structures/Message');