Fixed

• Prevent nesting plugin from breaking other plugins (#7563)
• Recursively collapse adjacent rules (#7565)
• Preserve source maps for generated CSS (#7588)
• Split box shadows on top-level commas only (#7479)
• Use local user CSS cache for @apply (#7524)
• Invalidate context when main CSS changes (#7626)
• Only add ! to selector class matching template candidate when using important modifier with multi-class selectors (#7664)
• Correctly parse and prefix animation names with dots (#7163)
• Fix extraction from template literal/function with array (#7481)
• Don't output unparsable arbitrary values (#7789)
• Fix generation of div:not(.foo) if .foo is never defined (#7815)
• Allow for custom properties in rgb, rgba, hsl and hsla colors (#7933)
• Remove autoprefixer as explicit peer-dependency to avoid invalid warnings in situations where it isn't actually needed (#7949)
• Ensure the percentage data type is validated correctly (#8015)

Changed

• Replace chalk with picocolors (#6039)
• Replace cosmiconfig with lilconfig (#6039)
• Update cssnano to avoid removing empty variables when minifying (#7818)