Remove warning for legacy 'source' configuration

Author: novemberborn

lib/cli.js

@@ -153,10 +153,6 @@ exports.run = async () => { // eslint-disable-line complexity
 		exit('The --concurrency or -c flag must be provided with a nonnegative integer.');
 	}
 
-	if ('source' in conf) {
-		exit('The \'source\' option has been renamed. Use \'sources\' instead.');
-	}
-
 	const ciParallelVars = require('ci-parallel-vars');
 	const Api = require('./api');
 	const VerboseReporter = require('./reporters/verbose');