omega-rpg: update urls, remove livecheck

[samford]

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omega-rpg was deprecated in #123330, as the website has disappeared. This PR updates the homepage and stable URLs to use the most recent archive.org snapshots of each.

This also removes the livecheck block, so the formula will be automatically skipped as deprecated.

[samford]

The build appears to be broken on Linux in some way:

gcc-11  omega.o abyss.o aux1.o aux2.o aux3.o char.o city.o command1.o command2.o command3.o country.o effect1.o effect2.o effect3.o etc.o env.o file.o gen1.o gen2.o guild1.o guild2.o house.o init.o inv.o item.o itemf1.o itemf2.o itemf3.o lev.o mmelee.o mmove.o mon.o move.o movef.o mspec.o mstrike.o mtalk.o priest.o save.o scr.o site1.o site2.o spell.o time.o trap.o util.o village.o -lncurses -ltermcap -o omega
/usr/bin/ld: abyss.o:(.bss+0x0): multiple definition of `Omegalib'; omega.o:(.bss+0x7a80): first defined here
[...omitted similar messages for the other files]
collect2: error: ld returned 1 exit status
make: *** [Makefile:39: omega] Error 1

Considering that the formula is deprecated and the sha256 is the same for the tarball snapshot on archive.org, how do we feel about just running this PR as syntax-only?

[BrewTestBot]

🤖 A scheduled task has triggered a merge.