chore(package): update @types/jest to version 25.1.0

Closes #23

Author: greenkeeper[bot]

package.json

@@ -25,7 +25,7 @@
   },
   "homepage": "https://github.com/nut-tree/secrets#readme",
   "devDependencies": {
-    "@types/jest": "24.0.23",
+    "@types/jest": "25.1.0",
     "@types/node": "12.12.14",
     "jest": "24.9.0",
     "ts-jest": "24.2.0",