Release 1.42.0

• [**] Button block - Add link picker to the block settings [https://github.com/WordPress/gutenberg/pull/26206]
• [**] Fix gradient picker causing crash in some themes (like Spearhead) [https://github.com/WordPress/gutenberg/pull/27307]
• [***] Adding support for selecting different unit of value in Cover and Columns blocks [https://github.com/WordPress/gutenberg/pull/26161]
• [*] Fix theme colors syncing with the editor [https://github.com/WordPress/gutenberg/pull/26821]
• Patch cover e2e test - #2827
• Stories: moved DEV flag to contact-info block availability declaration only - #2795
• Theme colors sync - #2788
• Support background colors for Group block - #2703