bsd-family-tree: OpenBSD 7.2 and DragonFly BSD 6.0.1

Add two releases to the tree.

While I'm here correct DragonFly BSD 6.2.1 position, it's
been released after FreeBSD 12.3.

MFC after: 3 days

(cherry picked from commit 7322a6bcacffcfcbb857a6899525ee51f4525ef9)