package/bind: security bump to version 9.11.28

Fixes the following security issue:

- CVE-2020-8625: When tkey-gssapi-keytab or tkey-gssapi-credential was
  configured, a specially crafted GSS-TSIG query could cause a buffer
  overflow in the ISC implementation of SPNEGO (a protocol enabling
  negotiation of the security mechanism to use for GSSAPI authentication).
  This flaw could be exploited to crash named.  Theoretically, it also
  enabled remote code execution, but achieving the latter is very difficult
  in real-world conditions

For details, see the advisory:
https://kb.isc.org/docs/cve-2020-8625

In addition, 9.11.26-27 fixed a number of issues, see the release notes for
details:
https://downloads.isc.org/isc/bind9/9.11.28/RELEASE-NOTES-bind-9.11.28.html

Drop now upstreamed patches, update the GPG key for the 2021-2022 variant
and update the COPYRIGHT hash for a change of year:

-Copyright (C) 1996-2020  Internet Systems Consortium, Inc. ("ISC")
+Copyright (C) 1996-2021  Internet Systems Consortium, Inc. ("ISC")

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/bind/bind.hash

@@ -1,4 +1,4 @@
-# Verified from https://ftp.isc.org/isc/bind9/9.11.25/bind-9.11.25.tar.gz.asc
-# with key 95CEDA256B1CA0A15F302FB59521A7ED5DACE918
-sha256  8491c24e5a3da68f421d0fcb946602c8d0ff963012fdd176b8026c8890f3a117  bind-9.11.25.tar.gz
-sha256  e316d9d12b3cc3600985d71011d7856f5ff93d28e748155a3a18171b32d98d8b  COPYRIGHT
+# Verified from https://ftp.isc.org/isc/bind9/9.11.28/bind-9.11.28.tar.gz.asc
+# with key 2455774D42FDFE6B9C383EB8FE1002BC5970811F
+sha256  1090cbe6caba37c404d1075887da7e5282ae9a2bc6172d722df15cd480975e74  bind-9.11.28.tar.gz
+sha256  cad49daa42654bc241762cd998630168a2542c8fd6fad3881e2eac1510bb6fcd  COPYRIGHT