Adds 8.1.0-rc1 and updates docker hub descriptions with new tags (#51) #331

Job	Run time
Generate Jobs	39s
unstable - test	2m 11s
unstable-alpine - test	2m 37s
8.1.0-rc1 - test	2m 9s
8.1.0-rc1-alpine - test	2m 32s
8.0.2 - test	1m 56s
8.0.2-alpine - test	2m 8s
7.2.8 - test	1m 57s
7.2.8-alpine - test	1m 59s
unstable - Build and push	43m 49s
unstable-alpine - Build and push	49m 23s
8.1.0-rc1 - Build and push	44m 28s
8.1.0-rc1-alpine - Build and push	49m 28s
8.0.2 - Build and push	36m 52s
8.0.2-alpine - Build and push	37m 57s
7.2.8 - Build and push	34m 6s
7.2.8-alpine - Build and push	36m 58s
Update DockerHub Description / Update Dockerhub description	3s
	5h 51m 12s

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