Update examples to use latest available checkout action v4.

Co-authored-by: Josh Gross <joshmgross@github.com>

* fix: cache-hit output

* fix: Output chache hit timing

* fix: Output chache hit timing

---------

Co-authored-by: Josh Gross <joshmgross@github.com>

* Fix Description for restore-keys at Readme

As previously the restore-keys were defined as an ordered lists which is
wrong as per the issue description where the actual format is a
multi-line string with one key per line.

* Added a space between the sentence of restore-keys description

While at the PR review it's been identified there's a need for a space
between the sentence

	```
	An ordered multiline string listing the prefix-matched keys,that are
	used for restoring stale cache if no cache hit occurred for key.
	```

where it's written as "prefix-matched keys,that are" this commit will
address the review comment and introduce a space between
"prefix-matched keys, that are" and change the sentence to

	```
	An ordered multiline string listing the prefix-matched keys, that are
        used for restoring stale cache if no cache hit occurred for key.
	```

* Change restore-keys description at cache/restore/action.yml and cache/action.yml

docs: update examples to v4

This workflow file publishes new action releases to the immutable action package of the same name as this repo.

This is part of the Immutable Actions project which is not yet fully released to the public. First party actions like this one are part of our initial testing of this feature.

Add workflow file for publishing releases to immutable action package

The `save-always` input added in v4 is not
working as intended due to
`post-if` expressions not supporting the input
context.
To avoid breaking users who have already added
this input to their workflows, it is being
deprecated now and will be removed
in the next major version (v5).
See #1315 for more details.

Co-authored-by: Josh Gross <joshmgross@github.com>

Co-authored-by: Josh Gross <joshmgross@github.com>

* Restore original behavior of `cache-hit` output

* Bump version to 4.1.1