chore(package): update ts-jest to version 23.1.4 (#17)

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "jest": "23.4.2",
     "jest-junit": "^5.1.0",
     "semantic-release": "^15.9.8",
-    "ts-jest": "23.1.3",
+    "ts-jest": "23.1.4",
     "ts-node": "^7.0.1",
     "tslint": "^5.11.0",
     "tslint-immutable": "^4.6.0",