Bump postcss from 7.0.39 to 8.4.49 (#2730)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alex <alex-ju@users.noreply.github.com>

Author: dependabot[bot]