[openssl/tools] baa1f4: Update the release HOWTO following the 3.1 release

[Matt Caswell]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/tools
  Commit: baa1f4310dbeebcd0785ee7281155f5a99f6bdcd
      https://github.com/openssl/tools/commit/baa1f4310dbeebcd0785ee7281155f5a99f6bdcd
  Author: Matt Caswell <matt at openssl.org>
  Date:   2023-03-14 (Tue, 14 Mar 2023)

  Changed paths:
    M HOWTO-make-a-release.md

  Log Message:
  -----------
  Update the release HOWTO following the 3.1 release

We now need to upload the release files to the "Releases" section of
github - so we update the HOWTO instructions accordingly.
This also fixes a minor error that was spotted during the release.

Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/tools/pull/128)