Bump src/main/resources/csl-styles from 568b636 to b90b81a (#12231)

Bumps [src/main/resources/csl-styles](https://github.com/citation-style-language/styles) from `568b636` to `b90b81a`.
- [Release notes](https://github.com/citation-style-language/styles/releases)
- [Commits](citation-style-language/styles@568b636...b90b81a)

---
updated-dependencies:
- dependency-name: src/main/resources/csl-styles
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Christoph <[email protected]>