Bump npm from 6.13.0 to 6.13.4

Bumps [npm](https://github.com/npm/cli) from 6.13.0 to 6.13.4.
- [Release notes](https://github.com/npm/cli/releases)
- [Changelog](https://github.com/npm/cli/blob/latest/CHANGELOG.md)
- [Commits](https://github.com/npm/cli/compare/v6.13.0...v6.13.4)

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

package.json

@@ -4,6 +4,6 @@
   "dependencies": {
     "discord.js": "^11.5.1",
     "mysql": "^2.17.1",
-    "npm": "^6.13.0"
+    "npm": "^6.13.4"
   }
 }