ports-mgmt/portconfig: Update to 0.6.2

• Change maintainership.
• New accessibility features:
  • ENVs to change the theme.
  • Install theme conf files.

ChangeLog: https://gitlab.com/alfix/portconfig/-/blob/main/CHANGELOG
PR: 283946
Reported by: Low Vision users https://forums.freebsd.org/threads/is-it-possible-to-change-the-ports-config-dialog-colours.94621/
Approved by: bapt
Sponsored by: The FreeBSD Foundation