Update @types/node requirement from ^11.9.6 to ^12.0.0 (#10)

Updates the requirements on [@types/node](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/node) to permit the latest version.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/node)

Signed-off-by: dependabot[bot] <support@dependabot.com>

package.json

@@ -35,7 +35,7 @@
 		"node-fetch": "^2.2.0"
 	},
 	"devDependencies": {
-		"@types/node": "^11.9.6",
+		"@types/node": "^12.0.0",
 		"eslint": "^5.6.1",
 		"eslint-config-amber": "^2.0.0",
 		"eslint-plugin-json": "^1.2.1",