feat: set a user agent when downloading CLI

[beanow-at-crabnebula]

The user agent will look something like: cloud-release/v0 (macOS; ARM64)
Where the v0 depends on how the caller referred to the action.

For example, when pinning to a sha hash that would be used instead.
cloud-release/6e3b1c716307d6f1759db4b3dd976aeda0e67b7b (macOS; ARM64)

In our test workflow, we're using a path (./) to refer to the action, so the action_ref is empty and we remove the version suffix like cloud-release (macOS; ARM64).

[github-actions]

Package Changes Through 70f1904

There are 1 changes which include action with patch

Planned Package Versions

The following package releases are the planned based on the context of changes in this pull request.

package	current	next
action	0.2.5	0.2.6

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[adam-crabnebula]

Confirmed working in QA