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

Closes #24

Author: greenkeeper[bot]

package.json

@@ -81,7 +81,7 @@
     "rimraf": "^3.0.0",
     "sinon": "^8.0.0",
     "style-loader": "^1.0.0",
-    "ts-jest": "^24.2.0",
+    "ts-jest": "^25.5.1",
     "ts-loader": "^6.0.4",
     "typescript": "^3.7.3",
     "webpack": "^4.41.2",