[Perl/perl5] 2de340: README: update bad version bumping for 5.38.0

[Ricardo Signes via perl5-changes]

  Branch: refs/heads/blead
  Home:   https://github.com/Perl/perl5
  Commit: 2de340afcf9cdab1e543a1a031c78c62a83b8b62
      
https://github.com/Perl/perl5/commit/2de340afcf9cdab1e543a1a031c78c62a83b8b62
  Author: Ricardo Signes <rjbs@semiotic.systems>
  Date:   2023-06-29 (Thu, 29 Jun 2023)

  Changed paths:
    M README.os2

  Log Message:
  -----------
  README: update bad version bumping for 5.38.0

(encore)