chore(package): update @types/node to version 13.1.1

Closes #58

Author: greenkeeper[bot]

package.json

@@ -33,7 +33,7 @@
     "@ethereumjs/config-tslint": "^1.1.1",
     "@types/bn.js": "^4.11.5",
     "@types/lru-cache": "^5.1.0",
-    "@types/node": "^12.7.5",
+    "@types/node": "^13.1.1",
     "@types/tape": "^4.2.33",
     "assemblyscript": "^0.8.1",
     "gulp": "^4.0.2",