chore(package): update @types/node to version 13.7.5

Closes #22

Author: greenkeeper[bot]

package.json

@@ -26,7 +26,7 @@
   "homepage": "https://github.com/nut-tree/secrets#readme",
   "devDependencies": {
     "@types/jest": "24.0.23",
-    "@types/node": "12.12.14",
+    "@types/node": "13.7.5",
     "jest": "24.9.0",
     "ts-jest": "24.2.0",
     "tslint": "5.20.1",