deps: upgrade co-body (#104)

change promise-based to async function

Author: popomore

.travis.yml

@@ -1,5 +1,6 @@
 language: node_js
 node_js:
-  - "7.6"
+  - "8"
+  - "10"
 script: "make test-travis"
 after_script: "npm install coveralls@2.10.0 && cat ./coverage/lcov.info | coveralls"

package.json

@@ -35,10 +35,10 @@
     "supertest": "^3.0.0"
   },
   "dependencies": {
-    "co-body": "^5.1.0",
+    "co-body": "^6.0.0",
     "copy-to": "^2.0.1"
   },
   "engines": {
-    "node": ">=7.6"
+    "node": ">=8.0.0"
   }
 }