Follow best practice and require process rather than use global (#1685)

lib/command.js

@@ -2,6 +2,7 @@ const EventEmitter = require('events').EventEmitter;
 const childProcess = require('child_process');
 const path = require('path');
 const fs = require('fs');
+const process = require('process');
 
 const { Argument, humanReadableArgName } = require('./argument.js');
 const { CommanderError } = require('./error.js');