Bump spec_tests/hed-specification from a9bf8b5 to 38a5993

Bumps [spec_tests/hed-specification](https://github.com/hed-standard/hed-specification) from `a9bf8b5` to `38a5993`.
- [Release notes](https://github.com/hed-standard/hed-specification/releases)
- [Commits](hed-standard/hed-specification@a9bf8b5...38a5993)

---
updated-dependencies:
- dependency-name: spec_tests/hed-specification
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>