chore(package): update ts-jest to version 23.0.1

Closes #33

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
     "jest": "^22.4.3",
     "sinon": "^4.5.0",
     "standard-version": "^4.3.0",
-    "ts-jest": "^22.4.2",
+    "ts-jest": "^23.0.1",
     "typescript": "^2.8.1"
   },
   "files": [