chore(package): update @types/jest to version 25.1.1

Closes #40

Author: greenkeeper[bot]

package.json

@@ -22,7 +22,7 @@
     "@types/dotenv": "^6.1.0",
     "@types/graphql": "^0.13.4",
     "@types/helmet": "^0.0.42",
-    "@types/jest": "^23.3.9",
+    "@types/jest": "^25.1.1",
     "@types/supertest": "^2.0.6",
     "coveralls": "^3.0.0",
     "del-cli": "^1.1.0",