chore(deps-dev): bump ajv from 7.1.1 to 7.2.1
chore(deps-dev): bump ajv from 7.1.1 to 7.2.1

Bumps [ajv](https://github.com/ajv-validator/ajv) from 7.1.1 to 7.2.1.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](https://github.com/ajv-validator/ajv/compare/v7.1.1...v7.2.1)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
vega/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite,vega/vega-lite