Bump spec_tests/hed-specification from 9a3ed49 to 3ad49f9

Bumps [spec_tests/hed-specification](https://github.com/hed-standard/hed-specification) from `9a3ed49` to `3ad49f9`.
- [Release notes](https://github.com/hed-standard/hed-specification/releases)
- [Commits](hed-standard/hed-specification@9a3ed49...3ad49f9)

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

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