[js] Bump the min supported version of Node to 6.9.0 (LTS)

Author: jleyba

javascript/node/selenium-webdriver/CHANGES.md

@@ -1,5 +1,6 @@
 ## v.next
 
+* (__NOTICE__) The minimum supported version of Node is now 6.9.0 LTS
 * Removed support for the SafariDriver browser extension. This has been
   replaced by Apple's safaridriver, which is included wtih Safari 10
   (available on OS X El Capitan and macOS Sierra).

javascript/node/selenium-webdriver/package.json

@@ -20,7 +20,7 @@
     "url": "https://github.com/SeleniumHQ/selenium.git"
   },
   "engines": {
-    "node": ">= 4.2.x"
+    "node": ">= 6.9.x"
   },
   "dependencies": {
     "adm-zip": "0.4.4",