Add support for RHEL 8 #27

Job	Run time
cleanup (debian-bullseye)	22s
cleanup (ubuntu-noble)	1m 27s
cleanup (gcc)	12s
cleanup (tools-rippled-prettier)	7s
cleanup (tools-rippled-clang-format)	9s
cleanup (debian-bookworm)	1m 21s
cleanup (rhel-9)	34s
cleanup (rhel-10)	19s
cleanup (ubuntu-jammy)	16s
cleanup (rhel-8)	3s
cleanup (tools-rippled-documentation)	9s
cleanup (tools-rippled-pre-commit)	15s
	5m 14s

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