docs: Update README.md to remove incubator wording (#8936) #2158

Job	Run time
Build and Push devlake builder	4m 30s
Get build timestamp	3s
Build and Push devlake base	14m 13s
Build and Push grafana image	1m 49s
Build and Push config-ui image	2m 54s
Build and cache devlake (arm64)	7m 21s
Build and cache devlake (amd64)	8m 17s
Build and Push devlake image	7m 55s
	47m 2s

Provide feedback