Docs: Replace version by 'current' in changes.rst

The file 'Documentation/process/changes.rst' states the listed
requirements are for the 4.x kernel version. However, there are
requirements updated for the 5.x version, as there might be in other
future versions. This patch updates it to 'latest' so the document won't
be outdated in the future.

Signed-off-by: Bruno Moreira-Guedes <codeagain@codeagain.dev>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/process/changes.rst

@@ -7,7 +7,7 @@ Intro
 =====
 
 This document is designed to provide a list of the minimum levels of
-software necessary to run the 4.x kernels.
+software necessary to run the current kernel version.
 
 This document is originally based on my "Changes" file for 2.0.x kernels
 and therefore owes credit to the same people as that file (Jared Mauch,