fix(subproviders): make web3-provider-engine types a 'dependency' so it's available to users of the library

packages/subproviders/package.json

@@ -39,6 +39,7 @@
         "@types/eth-lightwallet": "^3.0.0",
         "@types/ganache-core": "^2.1.0",
         "@types/hdkey": "^0.7.0",
+        "@types/web3-provider-engine": "^14.0.0",
         "bip39": "^2.5.0",
         "bn.js": "^4.11.8",
         "eth-lightwallet": "^3.0.1",
@@ -62,7 +63,6 @@
         "@types/mocha": "^2.2.42",
         "@types/node": "*",
         "@types/sinon": "^2.2.2",
-        "@types/web3-provider-engine": "^14.0.0",
         "chai": "^4.0.1",
         "chai-as-promised": "^7.1.0",
         "dirty-chai": "^2.0.1",