ICU-22533 Update BRS instructions for tagging release #1195

Job	Run time
clang-valgrind-test	9m 47s
clang-valgrind-intltest (utility)	8m 46s
clang-valgrind-intltest (normalize)	6m 8s
clang-valgrind-intltest (collator)	5m 51s
clang-valgrind-intltest (regex)	6m 21s
clang-valgrind-intltest (format)	27m 35s
clang-valgrind-intltest (translit)	8m 8s
clang-valgrind-intltest (rbbi)	7m 6s
clang-valgrind-intltest (rbnf)	7m 23s
clang-valgrind-intltest (rbnfrt)	7m 33s
clang-valgrind-intltest (icuserv)	7m 17s
clang-valgrind-intltest (idna)	6m 12s
clang-valgrind-intltest (convert)	6m 45s
clang-valgrind-intltest (rbnfp)	8m 10s
clang-valgrind-intltest (csdet)	4m 55s
clang-valgrind-intltest (spoof)	8m 17s
clang-valgrind-intltest (bidi)	6m 16s
	2h 22m 30s

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