chore(deps): update dependency typescript to v3 (#485)

Author: renovate[bot]

package.json

@@ -35,7 +35,7 @@
     "@types/node": "^10.0.3",
     "@types/once": "^1.4.0",
     "@types/p-limit": "^2.0.0",
-    "@types/pify": "^3.0.0",
+    "@types/pify": "^3.0.2",
     "@types/proxyquire": "^1.3.28",
     "@types/request": "^2.47.1",
     "@types/rimraf": "^2.0.2",
@@ -55,6 +55,7 @@
     "ncp": "^2.0.0",
     "nock": "^9.0.0",
     "once": "^1.4.0",
+    "pify": "^4.0.0",
     "post-install-check": "0.0.1",
     "proxyquire": "^2.0.0",
     "request": "^2.88.0",
@@ -63,7 +64,7 @@
     "source-map-support": "^0.5.6",
     "tmp": "0.0.33",
     "tslint": "^5.4.3",
-    "typescript": "~2.9.1"
+    "typescript": "~3.0.0"
   },
   "dependencies": {
     "@google-cloud/common": "^0.23.0",