chore(package): update peerDependencies (webpack v3.0.0) (#200)

Author: michael-ciniawsky

package.json

@@ -4,7 +4,7 @@
   "author": "Tobias Koppers @sokra",
   "description": "Offers a dev middleware for webpack, which arguments a live bundle to a directory",
   "peerDependencies": {
-    "webpack": "1 || ^2.6.1"
+    "webpack": "^1.0.0 || ^2.0.0 || ^3.0.0"
   },
   "dependencies": {
     "memory-fs": "~0.4.1",