deploy wf tweak

[hjoliver]

The "create conda envs" action in the deploy workflow isn't working.

It fails because of a path problem, and continue-on-error isn't working either (unexpected value: 'true')

I couldn't figure this out quickly so I deleted the whole block, and used this branch to deploy the 8.0b3 docs.

Probably want to fix it rather than merge this.

[hjoliver]

0s
Error: Can't find 'action.yml', 'action.yaml' or 'Dockerfile' under '/home/runner/work/cylc-doc/cylc-doc/.github/actions/create-conda-envs'.
  Did you forget to run actions/checkout before running your local action?
Error: .github/workflows/deploy.yml (Line: 94, Col: 28): Unexpected value 'true'
Error: The step failed and an error occurred when attempting to determine whether to continue on error.
Error: The template is not valid. .github/workflows/deploy.yml (Line: 94, Col: 28): Unexpected value 'true'

[hjoliver]

The undeploy workflow is also broken.

[MetRonnie]

and continue-on-error isn't working either (unexpected value: 'true')

This could be actions/runner#1483

[MetRonnie]

Closing as superseded by #358