Bump ajv from 8.12.0 to 8.15.0

Bumps [ajv](https://github.com/ajv-validator/ajv) from 8.12.0 to 8.15.0.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@v8.12.0...v8.15.0)

---
updated-dependencies:
- dependency-name: ajv
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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