Bump symfony/polyfill-mbstring from 1.23.0 to 1.23.1 (#41)

Bumps [symfony/polyfill-mbstring](https://github.com/symfony/polyfill-mbstring) from 1.23.0 to 1.23.1.
- [Release notes](https://github.com/symfony/polyfill-mbstring/releases)
- [Commits](symfony/polyfill-mbstring@v1.23.0...v1.23.1)

---
updated-dependencies:
- dependency-name: symfony/polyfill-mbstring
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>