package/fetchmail: security bump to version 6.4.22

package/fetchmail: security bump to version 6.4.22

Fixes the following security issues:

- CVE-2021-39272: Fetchmail before 6.4.22 fails to enforce STARTTLS session
  encryption in some circumstances, such as a certain situation with IMAP
  and PREAUTH.
  https://www.fetchmail.info/fetchmail-SA-2021-02.txt

Update COPYING hash for a clarification of the license situation with
openssl 3.x (which is Apache 2.0 licensed):

https://gitlab.com/fetchmail/fetchmail/-/commit/8eed56c21ca5bbdf3c00aaf74d807bcad8713ba9

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>