chore(package): update @types/node to version 13.7.0

Closes #25

Author: greenkeeper[bot]

package.json

@@ -36,7 +36,7 @@
   "license": "MIT",
   "devDependencies": {
     "@types/jest": "^24.0.15",
-    "@types/node": "^12.7.1",
+    "@types/node": "^13.7.0",
     "@typescript-eslint/eslint-plugin": "^1.11.0",
     "@typescript-eslint/parser": "^2.0.0",
     "coveralls": "^3.0.4",