Bump ajv and ajv-cli

Bumps [ajv](https://github.com/ajv-validator/ajv) to 6.12.6 and updates ancestor dependency [ajv-cli](https://github.com/ajv-validator/ajv-cli). These dependencies need to be updated together.


Updates `ajv` from 5.5.2 to 6.12.6
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@v5.5.2...v6.12.6)

Updates `ajv-cli` from 3.3.0 to 5.0.0
- [Release notes](https://github.com/ajv-validator/ajv-cli/releases)
- [Commits](ajv-validator/ajv-cli@v3.3.0...v5.0.0)

---
updated-dependencies:
- dependency-name: ajv
  dependency-type: indirect
- dependency-name: ajv-cli
  dependency-type: direct:development
...

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