Bump ajv, eslint, eslint-config-airbnb and eslint-config-airbnb-base

Bumps [ajv](https://github.com/ajv-validator/ajv) to 6.12.6 and updates ancestor dependencies [ajv](https://github.com/ajv-validator/ajv), [eslint](https://github.com/eslint/eslint), [eslint-config-airbnb](https://github.com/airbnb/javascript) and [eslint-config-airbnb-base](https://github.com/airbnb/javascript). 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 `eslint` from 4.19.1 to 8.51.0
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/main/CHANGELOG.md)
- [Commits](eslint/eslint@v4.19.1...v8.51.0)

Updates `eslint-config-airbnb` from 17.0.0 to 17.1.1
- [Commits](airbnb/javascript@eslint-config-airbnb-v17.0.0...eslint-config-airbnb-v17.1.1)

Updates `eslint-config-airbnb-base` from 13.0.0 to 13.2.0
- [Commits](airbnb/javascript@eslint-config-airbnb-base-v13.0.0...eslint-config-airbnb-base-v13.2.0)

---
updated-dependencies:
- dependency-name: ajv
  dependency-type: indirect
- dependency-name: eslint
  dependency-type: direct:development
- dependency-name: eslint-config-airbnb
  dependency-type: direct:development
- dependency-name: eslint-config-airbnb-base
  dependency-type: direct:development
...

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