chore(package): update ts-jest to version 25.5.0

Closes #120

Author: greenkeeper[bot]

package.json

@@ -69,7 +69,7 @@
     "pre-commit": "^1.2.2",
     "rimraf": "^2.6.3",
     "supertest": "^3.4.2",
-    "ts-jest": "^24.0.1",
+    "ts-jest": "^25.5.0",
     "tslint": "^5.15.0",
     "tslint-config-airbnb": "^5.11.1",
     "typescript": "^3.4.1"