docs: Don't reference the ZLib license in license-rules.rst

We never had a file called LICENSES/other/ZLib in the tree, so don't
reference it.  Instead mention the GPL v1 as an (bad) example.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/process/license-rules.rst

@@ -255,9 +255,9 @@ kernel, can be broken down into:
    Contains the Internet Systems Consortium license text and the required
    metatags::
 
-      LICENSES/other/ZLib
+      LICENSES/other/GPL-1.0
 
-   Contains the ZLIB license text and the required metatags.
+   Contains the GPL version 1 license text and the required metatags.
 
    Metatags: