Bump tests/specifications from c13d23b to 5b15fd3 (#1743)

Bumps [tests/specifications](https://github.com/mongodb/specifications) from `c13d23b` to `5b15fd3`.
- [Release notes](https://github.com/mongodb/specifications/releases)
- [Commits](mongodb/specifications@c13d23b...5b15fd3)

---
updated-dependencies:
- dependency-name: tests/specifications
  dependency-version: 5b15fd307b7ec06dbafc57e3c252f7ae3b8c4e46
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]