fix(deps): update dependency postcss@<8.5.10 to >=8.5.18 [security] (#358)

Signed-off-by: Renovate Bot <bot@renovateapp.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Daniel Bannert <d.bannert@anolilab.de>

Author: renovate[bot]