README: Tweak section about Incus creation #297

Job	Run time
Code	3m 7s
Documentation	7m 44s
Client (1.20.x, ubuntu-latest)	1m 7s
System (1.20.x, cluster, dir)	8m 33s
Client (1.20.x, macos-latest)	1m 49s
System (1.20.x, cluster, btrfs)	8m 33s
Client (1.20.x, windows-latest)	1m 58s
System (1.20.x, cluster, lvm)	8m 33s
System (1.20.x, cluster, zfs)	8m 33s
System (1.20.x, cluster, ceph)	8m 33s
System (1.20.x, cluster, random)	8m 32s
System (1.20.x, standalone, dir)	8m 34s
System (1.20.x, standalone, btrfs)	8m 31s
System (1.20.x, standalone, lvm)	8m 32s
System (1.20.x, standalone, zfs)	8m 32s
System (1.20.x, standalone, ceph)	8m 38s
System (1.20.x, standalone, random)	8m 34s
System (stable, cluster, dir)	8m 32s
System (stable, standalone, dir)	8m 32s
System (tip, cluster, dir)	8m 34s
System (tip, standalone, dir)	8m 32s
	2h 32m 33s

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