chore(deps-dev): bump postcss-discard-comments from 7.0.6 to 7.0.8

Bumps [postcss-discard-comments](https://github.com/cssnano/cssnano) from 7.0.6 to 7.0.8.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/postcss-discard-comments@7.0.6...postcss-discard-comments@7.0.8)

---
updated-dependencies:
- dependency-name: postcss-discard-comments
  dependency-version: 7.0.8
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]