build(deps): bump postcss-merge-longhand from 6.0.0 to 6.0.1

Bumps [postcss-merge-longhand](https://github.com/cssnano/cssnano) from 6.0.0 to 6.0.1.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/postcss-merge-longhand@6.0.0...postcss-merge-longhand@6.0.1)

---
updated-dependencies:
- dependency-name: postcss-merge-longhand
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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