Bump testdata/specifications from 1c1500a to f4c0bbd

Bumps [testdata/specifications](https://github.com/mongodb/specifications) from `1c1500a` to `f4c0bbd`.
- [Release notes](https://github.com/mongodb/specifications/releases)
- [Commits](mongodb/specifications@1c1500a...f4c0bbd)

---
updated-dependencies:
- dependency-name: testdata/specifications
  dependency-version: f4c0bbdbf8a8560580c947ca2c331794431a0c78
  dependency-type: direct:production
...

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

Author: dependabot[bot]