chore(deps-dev): bump cohere from 5.8.1 to 5.15.0

Bumps cohere from 5.8.1 to 5.15.0.

---
updated-dependencies:
- dependency-name: cohere
  dependency-version: 5.15.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]