fix(package): update compression to version 1.7.0

Author: greenkeeper[bot]

package.json

@@ -16,7 +16,7 @@
   "dependencies": {
     "body-parser": "1.17.2",
     "co": "~4.6.0",
-    "compression": "~1.6.2",
+    "compression": "~1.7.0",
     "connect-flash": "~0.1.1",
     "connect-mongo": "~1.3.1",
     "cookie-parser": "~1.4.1",