Bump ajv from 6.12.2 to 6.12.6
Bumps [ajv](https://github.com/ajv-validator/ajv) from 6.12.2 to 6.12.6.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](https://github.com/ajv-validator/ajv/compare/v6.12.2...v6.12.6)
---
updated-dependencies:
- dependency-name: ajv
dependency-type: indirect
...
Signed-off-by: dependabot[bot] <[email protected]>