chore(package): update ts-jest to version 25.5.1

Closes #17

Author: greenkeeper[bot]

package.json

@@ -79,7 +79,7 @@
     "rollup-plugin-sourcemaps": "^0.4.2",
     "rollup-plugin-typescript2": "^0.24.3",
     "shelljs": "^0.8.3",
-    "ts-jest": "^24.1.0",
+    "ts-jest": "^25.5.1",
     "ts-node": "^8.4.1",
     "tslint": "^5.11.0",
     "tslint-config-prettier": "^1.15.0",