chore: correct step output key in readme

[willarmiros]

Just a quick doc update - seems like the output keyname for a release being created has changed and it wasn't reflected in docs. See this output from release-please for evidence: https://github.com/willarmiros/test-package-lock-repo/runs/3617929254?check_suite_focus=true#step:3:4

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Warning: This pull request is touching the following templated files:

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[willarmiros]

@googlebot I signed it!

[chingor13]

I don't think this is correct: https://github.com/google-github-actions/release-please-action/blob/main/index.js#L56

[willarmiros]

I think we were both mistaken - it looks like releases_created is actually set as output when there is any release: https://github.com/google-github-actions/release-please-action/blob/973b63d3d58b9a5a9fed0dd512501ad5a9ab319b/index.js#L49

Whereas release_created wasn't removed as I initially thought, but is only set if you are releasing a package at the root of the repo(?) Regardless, IMO it would be more correct to use the output that is always set in the example code to cover more use cases.

[bcoe]

@willarmiros are you using the manifest releaser, and this is why the releases_created is the variable you needed?

What about a compromise and updating the documents for the manifest functionality to include an example of the GitHub action?

[willarmiros]

@bcoe ah yes I am using the manifest releaser, I guess the behavior is pretty different from the single-package option. I can try to add a sample action workflow to this PR in https://github.com/googleapis/release-please/blob/main/docs/manifest-releaser.md.

Given manifest releases would typically be for monorepos, would it be ok to include lerna in the example for running release-please and publishing to NPM?

[bcoe]

Given manifest releases would typically be for monorepos, would it be ok to include lerna in the example for running release-please and publishing to NPM?

@willarmiros for sure, I'd be interested in seeing how you recommend doing this for my own benefit.

stale

[bcoe]

@willarmiros please feel free to dust this off if you'd like to add docs about lerna (I think this would be valuable for folks).

[willarmiros]

@bcoe see #1100