Fix `"inngest/next"` types not inferring from `defineProperties`

[jpwilliams]

Summary

Fixes #340, ensuring the return type of "inngest/next"'s serve() is correctly inferred.

Fuller integration tests for the app router will come in #341.

Checklist

• [ ] Added a docs PR that references this PR N/A
• [ ] Added unit/integration tests N/A #341
• [x] Added changesets if applicable

Related

• Fixes #340

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: edfad191812c0dc0e057535f6e7fec93cbdbc428

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | ------- | ----- | | inngest | Patch |

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[jpwilliams]

@djfarrelly: LGTM - Weird typescript stuff on this one!

Yeah. v2 got away with this because we always returned any. #341 adds integration tests for the app router which will catch this in the future.