Add a container definition for Rocky Linux 9.3 #60

Job	Run time
build (centos, 7, centos-7, centos-7/Containerfile)	7m 12s
build (rockylinux, 8, rockylinux-8, rockylinux-8/Containerfile)	5m 8s
build (rockylinux, 8.6, rockylinux-8, rockylinux-8/Containerfile-8.6)	6m 52s
build (rockylinux, 8.7, rockylinux-8, rockylinux-8/Containerfile-8.7)	6m 50s
build (rockylinux, 8.8, rockylinux-8, rockylinux-8/Containerfile-8.8)	7m 49s
build (rockylinux, 8.9, rockylinux-8, rockylinux-8/Containerfile-8.9)	5m 49s
build (rockylinux, 9, rockylinux-9, rockylinux-9/Containerfile)	7m 10s
build (rockylinux, 9.0, rockylinux-9, rockylinux-9/Containerfile-9.0)	6m 45s
build (rockylinux, 9.1, rockylinux-9, rockylinux-9/Containerfile-9.1)	7m 14s
build (rockylinux, 9.2, rockylinux-9, rockylinux-9/Containerfile-9.2)	7m 20s
build (rockylinux, 9.3, rockylinux-9, rockylinux-9/Containerfile-9.3)	7m 6s
build (leap, 15, leap, leap/Containerfile.15)	6m 52s
build (leap, latest, leap, leap/Containerfile)	6m 50s
	1h 28m 57s

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