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

Closes #46

Author: greenkeeper[bot]

package.json

@@ -127,7 +127,7 @@
     "standard-version": "5.0.2",
     "strip-json-comments-cli": "1.0.1",
     "tiny-glob": "0.2.6",
-    "ts-jest": "24.0.2",
+    "ts-jest": "25.5.0",
     "tslib": "1.9.3",
     "tslint": "5.16.0",
     "tslint-config-prettier": "1.18.0",