Update multi-step workflow tutorial

[bnubald]

The Cylc workflow tutorial looks to be out of date:

https://github.com/cedadev/jasmin-workshop/tree/master/tutorials/tut02

No cylc1 server that I could connect to, looks like it should be updated to use cylc2 server, and changes for Cylc 8 support:

• Change in commands (some rose commands now replaced by cylc equivalents)
• Update suite configuration file for Cylc 8.
• Update README to reflect these changes.

Relevant issue: #79