fix: type declarations for configs

[thor-juhasz]

Adds proper types for the configs (in the yet unreleased index.d.ts).

If this PR gets rejected, note that the configs key is still incorrectly typed with the current index.d.ts file.

If only a fix for that is wanted, without the types for the configs themselves, consider this:

  configs: {
-    [name in keyof ConfigName]: any
+    [name in ConfigName]: any
  }

[FloEdelmann]

Thanks, this looks good! 🙂

[ota-meshi]

Thank you!