Add 22.03.1 and 21.02.4 to ASU supported versions

[mangajews]

22.03.1 and 21.02.4 were officially announced today, but the ASU live configuration is not updated in-sync. This affects customized builds via the firmware selector, which is directly linked in the new version announcements.

Multiple users do expect to be able to make custom builds immediately after new releases, as evidenced by various forum.openwrt.org posts.

• https://forum.openwrt.org/t/the-openwrt-firmware-selector/81721/262
• https://forum.openwrt.org/t/openwrt-22-03-1-first-service-release/139424/5

Can the ASU live configuration be updated just by making a PR on branches.yml, or is there more to it?