Fix a TS error when using Inngest in projects with composite setting (

#385)

## Summary
<!-- Succinctly describe your change, providing context, what you've
changed, and why. -->
Adds some type exports to `index.ts` that fix a TS error in `composite`
projects.


## Checklist
<!-- Tick these items off as you progress. -->
<!-- If an item isn't applicable, ideally please strikeout the item by
wrapping it in "~~"" and suffix it with "N/A My reason for skipping
this." -->
<!-- e.g. "- [ ] ~~Added tests~~ N/A Only touches docs" -->

- [ ] ~~Added a [docs PR](https://github.com/inngest/website) that
references this PR~~ N/A
- [ ] ~~Added unit/integration tests~~ N/A
- [x] Added changesets if applicable

## Related
Fixes #384

---------

Co-authored-by: Jack Williams <1736957+jpwilliams@users.noreply.github.com>

.changeset/strange-experts-punch.md

@@ -0,0 +1,5 @@
+---
+"inngest": patch
+---
+
+Add exports for `InngestFunction`, `FunctionTrigger`, and `Handler` types to fix a TypeScript error when using Inngest in projects with `composite` setting in `tsconfig`.

packages/inngest/src/index.ts

@@ -16,6 +16,7 @@ export type {
 } from "./components/Inngest";
 export { InngestCommHandler } from "./components/InngestCommHandler";
 export type { ServeHandlerOptions } from "./components/InngestCommHandler";
+export type { InngestFunction } from "./components/InngestFunction";
 export { InngestMiddleware } from "./components/InngestMiddleware";
 export type {
   MiddlewareOptions,
@@ -41,6 +42,8 @@ export type {
   FailureEventArgs,
   FailureEventPayload,
   FunctionOptions,
+  FunctionTrigger,
+  Handler,
   LogLevel,
   RegisterOptions,
   StepOptions,