Fix which contract artifacts are published (#570)

Author: nmlinaric

package.json

@@ -7,10 +7,13 @@
   "files": [
     "dist",
     "build/contracts/Bridge.json",
+    "build/contracts/Forwarder.json",
     "build/contracts/ERC20Handler.json",
     "build/contracts/ERC721Handler.json",
+    "build/contracts/ERC1155Handler.json",
     "build/contracts/GenericHandler.json",
-    "build/contracts/HandlerHelpers.json"
+    "build/contracts/BasicFeeHandler.json",
+    "build/contracts/FeeHandlerWithOracle.json"
   ],
   "directories": {
     "test": "test"