Build: Bump fastavro from 1.11.1 to 1.12.0

Bumps [fastavro](https://github.com/fastavro/fastavro) from 1.11.1 to 1.12.0.
- [Release notes](https://github.com/fastavro/fastavro/releases)
- [Changelog](https://github.com/fastavro/fastavro/blob/master/ChangeLog)
- [Commits](fastavro/fastavro@1.11.1...1.12.0)

---
updated-dependencies:
- dependency-name: fastavro
  dependency-version: 1.12.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]