Bump ajv and fsevents

Bumps [ajv](https://github.com/ajv-validator/ajv) and [fsevents](https://github.com/fsevents/fsevents). These dependencies needed to be updated together.

Updates `ajv` from 4.11.8 to 6.12.6
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@4.11.8...v6.12.6)

Updates `fsevents` from 1.1.3 to 1.2.13
- [Release notes](https://github.com/fsevents/fsevents/releases)
- [Commits](fsevents/fsevents@v1.1.3...v1.2.13)

---
updated-dependencies:
- dependency-name: ajv
  dependency-type: indirect
- dependency-name: fsevents
  dependency-type: indirect
...

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

Author: dependabot[bot]