Add semicolon for tdd exports

test/averageBy/averageBy.js

@@ -1,4 +1,4 @@
 const averageBy = (arr, fn) =>
 arr.map(typeof fn === 'function' ? fn : val => val[fn]).reduce((acc, val) => acc + val, 0) /
 arr.length;
-module.exports = averageBy
+module.exports = averageBy;