ICU-22533 Update BRS instructions for tagging release #1194

Job	Run time
clang-valgrind-test	10m 8s
clang-valgrind-intltest (utility)	8m 26s
clang-valgrind-intltest (normalize)	7m 12s
clang-valgrind-intltest (collator)	5m 13s
clang-valgrind-intltest (regex)	5m 2s
clang-valgrind-intltest (format)	16m 3s
clang-valgrind-intltest (translit)	7m 18s
clang-valgrind-intltest (rbbi)	9m 6s
clang-valgrind-intltest (rbnf)	6m 16s
clang-valgrind-intltest (rbnfrt)	7m 33s
clang-valgrind-intltest (icuserv)	4m 53s
clang-valgrind-intltest (idna)	5m 23s
clang-valgrind-intltest (convert)	9m 6s
clang-valgrind-intltest (rbnfp)	9m 29s
clang-valgrind-intltest (csdet)	5m 12s
clang-valgrind-intltest (spoof)	6m 13s
clang-valgrind-intltest (bidi)	8m 45s
	2h 11m 18s

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