package/samba4: security bump version to 4.21.6

Release notes:
https://www.samba.org/samba/history/samba-4.21.5.html
https://www.samba.org/samba/history/samba-4.21.6.html

Version 4.21.6 fixes CVE-2025-0620:
https://www.samba.org/samba/security/CVE-2025-0620.html

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Julien Olivain <ju.o@free.fr>
(cherry picked from commit cae9a45e55b47dc08eb17e0610340cbb30903cf5)
Signed-off-by: Thomas Perale <thomas.perale@mind.be>

package/samba4/samba4.hash

@@ -1,4 +1,4 @@
 # Locally calculated after checking pgp signature
-# https://download.samba.org/pub/samba/stable/samba-4.21.4.tar.asc
-sha256  50acf030db0ce6be1ee8a6c3a7636e54576c60a7f814e64becfa840f7b30eced  samba-4.21.4.tar.gz
+# https://download.samba.org/pub/samba/stable/samba-4.21.6.tar.asc
+sha256  681bad60f57959436350751bc89e893b8c106ac882cc7420f93f419e1d188688  samba-4.21.6.tar.gz
 sha256  8ceb4b9ee5adedde47b31e975c1d90c73ad27b6b165a1dcd80c7c545eb65b903  COPYING

package/samba4/samba4.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-SAMBA4_VERSION = 4.21.4
+SAMBA4_VERSION = 4.21.6
 SAMBA4_SITE = https://download.samba.org/pub/samba/stable
 SAMBA4_SOURCE = samba-$(SAMBA4_VERSION).tar.gz
 SAMBA4_INSTALL_STAGING = YES