chore(package): update ts-jest to version 23.0.0 (buehler#74)

Author: greenkeeper[bot]

package.json

@@ -44,7 +44,7 @@
  "jest": "^23.2.0",
  "mock-fs": "^4.5.0",
  "semantic-release": "^15.6.0",
- "ts-jest": "^22.4.6",
+ "ts-jest": "^23.0.0",
  "tslint": "^5.10.0",
  "tsutils": "^2.27.1",
  "typedoc": "^0.11.1"