Bump pest_derive from 2.7.7 to 2.7.8

Bumps [pest_derive](https://github.com/pest-parser/pest) from 2.7.7 to 2.7.8.
- [Release notes](https://github.com/pest-parser/pest/releases)
- [Commits](pest-parser/pest@v2.7.7...v2.7.8)

---
updated-dependencies:
- dependency-name: pest_derive
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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