Update dependency ts-jest to v22.4.6

Author: renovate-bot

package.json

@@ -36,7 +36,7 @@
     "codecov": "3.0.1",
     "jest": "22.4.4",
     "standard": "10.0.3",
-    "ts-jest": "22.4.4",
+    "ts-jest": "22.4.6",
     "tslint": "5.9.1",
     "typescript": "2.8.3"
   },