feat(deps): Update singer-sdk requirement from ~=0.37.0a4 to ~=0.38.0a2

Updates the requirements on [singer-sdk](https://github.com/meltano/sdk) to permit the latest version.
- [Release notes](https://github.com/meltano/sdk/releases)
- [Changelog](https://github.com/meltano/sdk/blob/main/CHANGELOG.md)
- [Commits](meltano/sdk@v0.37.0a4...v0.38.0a2)

---
updated-dependencies:
- dependency-name: singer-sdk
  dependency-type: direct:production
...

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

pyproject.toml

@@ -31,7 +31,7 @@ dynamic = [
 ]
 dependencies = [
   "requests~=2.31",
-  "singer-sdk~=0.37.0a4",
+  "singer-sdk~=0.38.0a2",
 ]
 optional-dependencies.dev = [
   "tap-polarsh[testing,typing]",