4.13.0-rc1

What's Changed

• API Stop using deprecated API by @emteknetnz in #2794
• API Stop using deprecated API by @emteknetnz in #2799
• MNT Update unit test to detect invalid HTML by @emteknetnz in #2808
• FIX Behat test by @emteknetnz in #2815
• API Remove pointless subitem_class config by @maxime-rainville in #2817
• API Deprecate legacy tasks by @emteknetnz in #2819
• MNT Update unit test to work with both HTML4Value and HTML5Value by @emteknetnz in #2827
• API Mark moved classes in silverstripe-admin module as deprecated by @sabina-talipova in #2840
• ENH Update translations by @emteknetnz in #2841
• MNT Revert erroneous dependency changes by @GuySartorelli in #2844

Full Changelog: 4.12.0...4.13.0-rc1