docs: add info how to access monorepo path outputs (#1003)

Added description how to access monorepo step result outputs using []
syntax

It took me several hours to figure out how to access the outputs of
these monorepo packages. Hopefully, this will save others some time

---------

Signed-off-by: Wolfram Sokollek <8589105+WolfSoko@users.noreply.github.com>
Co-authored-by: Jeff Ching <chingor@google.com>

README.md

@@ -200,6 +200,14 @@ This prefix allows you to distinguish values for different releases.
 | `<path>--patch`           | Number representing patch semver value                                                                     |
 | `<path>--sha`             | sha that a GitHub release was tagged at                                                                    |
 
+If the path contains `/` you can access the outputs by using javascript like property access `steps.release.outputs[<path>--...]` 
+e.g.:
+
+```yaml
+run: npm publish --workflow packages/my-module
+if: ${{ steps.release.outputs['packages/my-module--release_created'] }}
+```
+
 ## How release please works
 
 Release Please automates CHANGELOG generation, the creation of GitHub releases,