chore: Work around fpr running the tests in Node.js 6

Author: prantlf

test/typings.test.ts

@@ -1,6 +1,6 @@
 import {
   convertToLocalTime, convertToTimeZone, parseFromString, parseFromTimeZone, formatToTimeZone
-} from '..'
+} from '../src'
 
 declare function test(label: string, callback: Function)