Ensure support for typescript@~5.7.0 (#760)

## Summary
<!-- Succinctly describe your change, providing context, what you've
changed, and why. -->

Ensures support for `typescript@~5.7.0` by adding a new PR check. See
[Announcing TypeScript 5.7 -
TypeScript](https://devblogs.microsoft.com/typescript/announcing-typescript-5-7/).

Ideally we would take advantage of the new
`rewriteRelativeImportExtensions` added in microsoft/TypeScript#59767
which would allow us to correctly import `.ts` extensions instead of
requiring `.js`, ready for better Deno/Bun support, as well as Node
support when running `.ts` files directly.

Unfortunately, `typescript<5.0.0` doesn't support the compiled output;
we'll have to wait for v4 to use that.

## 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 KTLO
- [x] Added unit/integration tests
- [x] Added changesets if applicable

## Related

- https://devblogs.microsoft.com/typescript/announcing-typescript-5-7/
- microsoft/TypeScript#59767

.changeset/weak-worms-scream.md

@@ -0,0 +1,7 @@
+---
+"inngest": patch
+---
+
+Ensure support for `typescript@~5.7.0`
+
+No notable changes have been made, though minor TypeScript versions often affect transpiled outputs.

.github/workflows/pr.yml

@@ -59,6 +59,7 @@ jobs:
       matrix:
         tsVersion:
           - "latest"
+          - "~5.7.0"
           - "~5.6.0"
           - "~5.5.0"
           - "~5.4.0"

packages/inngest/package.json

@@ -243,7 +243,7 @@
     "shx": "^0.3.4",
     "ts-jest": "^29.1.0",
     "tsx": "^3.12.7",
-    "typescript": "~5.6.2"
+    "typescript": "~5.7.2"
   },
   "volta": {
     "node": "18.12.1",

packages/inngest/tsconfig.json

@@ -18,6 +18,19 @@
     "resolveJsonModule": true,
     "noUncheckedIndexedAccess": true,
     "strictNullChecks": true,
+
+    // In TS 5.7+ we can use these to ensure we can import `.ts` extensions and
+    // have them compile to `.js` imports. This also then means we're compatible
+    // with Node/Deno/Bun's TS running instead of leaking compilation
+    // requirements into the source code.
+    //
+    // Importing `.ts` extensions fails miserably when using compiled output
+    // with TS<5.0 though, so we must keep this commented out and unactioned
+    // until we can safely assume at least TS>=5.0.
+    //
+    // "rewriteRelativeImportExtensions": true,
+    // "allowImportingTsExtensions": true,
+
     "paths": {
       "inngest": ["./src"],
       "inngest/*": ["./src/*"],