Update Node in Travis

Author: wooorm

.travis.yml

@@ -1,7 +1,7 @@
 language: node_js
 node_js:
 - '4.0'
-- '8.0'
+- '9.0'
 sudo: false
 after_script: bash <(curl -s https://codecov.io/bash)
 deploy:
@@ -11,7 +11,7 @@ deploy:
       secure: L2CV9310heZFCuusDtSz7fxjHwpjrokljlMeVbyd/wiBQzy+bIr0RTMD+UxIXolxNEqjec1z9LKn5bx7B9S1oGJW6N22VmyUXBwWKJATptsV/MmO62ab68wJvefuLQKk/m2MbGe5ZwQ2BH9YC6ImKs2L1wp7oOjo1eN2q8S8KeE=
     on:
       tags: true
-      node: '4.0'
+      node: '9.0'
   - provider: releases
     api_key:
       secure: gzvWsnNs268yLRD836U722pOohl51UxxUko05oEUJvjasiR0oqCKdSReF3ggStBerhSbvsiMppPOeRP/nMtzVoA8JnbvgfFJ+0otT5ouBkiIWAZIXrrYR52m2AZ4I2ICBhyZdDwiD7rtRwfA3k9UNc6X2IG0KGgYVOiElOZiwDE=
@@ -20,4 +20,4 @@ deploy:
       - "unist-util-inspect.min.js"
     on:
       tags: true
-      node: '8.0'
+      node: '9.0'