Add Background Support to Cover Block

functions.php

add_filter( 'block_type_metadata_settings', 'filter_metadata_registration', 10, 2 );

public function filter_metadata_registration( $settings, $metadata ) {

		if ( 'core/cover' == $metadata['name'] ) {
			if ( is_array( $settings['supports']['color'] ) ) {
				$settings['supports']['color']['background'] = true;
			} else {
				$settings['supports']['color'] = array(
					'background' => true,
                                        'text' => false, /** text color gets overridden by light/dark classes **/
				);
			}
		} elseif ( 'core/quote' == $metadata['name'] ) {

			if ( is_array( $settings['supports']['color'] ) ) {
				$settings['supports']['color']['text'] = true;
			} else {
				$settings['supports']['color'] = array(
					'text'       => true,
					'background' => false,
				);
			}
		}
		return $settings;
	}