chore(deps): pin dependencies (#163)

Author: renovate-bot

package-lock.json

@@ -36,17 +36,17 @@
   "author": "Google Inc.",
   "license": "Apache-2.0",
   "devDependencies": {
-    "@types/body-parser": "^1.17.0",
-    "@types/express": "^4.16.1",
-    "@types/minimist": "^1.2.0",
-    "@types/mocha": "^5.2.6",
-    "@types/node": "^11.9.5",
-    "@types/on-finished": "^2.3.1",
-    "@types/supertest": "^2.0.8",
-    "gts": "^1.0.0-0",
-    "mocha": "^6.0.0",
-    "power-assert": "^1.6.1",
-    "supertest": "^3.4.2",
-    "typescript": "^3.3.3333"
+    "@types/body-parser": "1.17.0",
+    "@types/express": "4.17.0",
+    "@types/minimist": "1.2.0",
+    "@types/mocha": "5.2.7",
+    "@types/node": "11.13.13",
+    "@types/on-finished": "2.3.1",
+    "@types/supertest": "2.0.8",
+    "gts": "1.0.0",
+    "mocha": "6.1.4",
+    "power-assert": "1.6.1",
+    "supertest": "3.4.2",
+    "typescript": "3.5.1"
   }
 }