Add a users paragraph to the README

Author: webknjaz

README.md

@@ -3,10 +3,16 @@
 A GitHub Action to unpack a source distribution package (tarball / `.tar.gz`) into the current workspace
 
 
+## Any users?
+
+At the moment, it is used by the [@CherryPy] upstream, more to come.
+
+
 ## License
 
 The contents of this project is released under the
 [BSD 3-clause license].
 
 
 [BSD 3-clause license]: LICENSE
+[@CherryPy]: https://github.com/cherrypy