Log Message:
samba4: updated to 4.21.3

Changes since 4.21.2

* BUG 15701: More possible replication loops against Azure AD.
* BUG 15697: Compound rename from Mac clients can fail with
  NT_STATUS_INTERNAL_ERROR if the file has a lease.
* BUG 15724: vfs crossrename seems not work correctly.
* BUG 6750: After 'machine password timeout' /etc/krb5.keytab is not updated.
* BUG 15771: Memory leak wbcCtxLookupSid.
* BUG 15765: Fix heap-user-after-free with association groups.
* BUG 15758: Segfault in vfs_btrfs.
* BUG 15755: Avoid event failure race when disabling an event script.
* BUG 15724: vfs crossrename seems not work correctly.