changelog: a path input for a checkout that is not the workspace itself

decePubClient fetches itself into a folder of its own.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -187,6 +187,7 @@ when there is none, and otherwise replaces only what sits between `<!-- changelo
 
 | Input | | |
 |---|---|---|
+| `path` | `.` | the git checkout to read, when it is not the workspace itself |
 | `prefix` | `v` | the tags of this kind of release |
 | `tag` | the tag that started the run | the release being made; empty on a branch, which writes everything since the newest tag as `unreleased` |
 | `name` | the repository's name | the product's name in headings |