Rename 'attach' to 'attach-resource'.

[anastasiamac]

Description of change

This command was overlooked in major rename effort that occurred on a cusp of Juju 2.x.
This is needed to comply with standard naming convention and to add clarity to command intent.

Previous command name 'attach' is now an alias for 'attach-resource' for backward compatibility.

QA steps

1. 'juju help commands' has both 'attach' and 'attach-resource'
2. running 'juju attach-resource' yields the same result as running 'juju attach'

Documentation changes

Yes!
All references to 'juju attach' in documentation should be changed to 'juju attach-resource'.

Bug reference

Part of https://bugs.launchpad.net/juju/+bug/1707564

[hmlanigan]

nit: update the comment?

[anastasiamac]

$$merge$$

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju

[anastasiamac]

@pmatulis,

This change may require documentation update.