package/postgresql: security bump version to 15.6

Release notes: https://www.postgresql.org/docs/release/15.6/

Fixes CVE-2024-0985: PostgreSQL non-owner REFRESH MATERIALIZED VIEW
CONCURRENTLY executes arbitrary SQL

Update COPYRIGHT hash for a change in copyright year (2023->2024).

Signed-off-by: Maxim Kochetkov <fido_max@inbox.ru>
[Peter: Fix COPYRIGHT hash, extend commit message]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/postgresql/postgresql.hash

@@ -1,4 +1,4 @@
-# From https://ftp.postgresql.org/pub/source/v15.4/postgresql-15.5.tar.bz2.sha256
-sha256  8f53aa95d78eb8e82536ea46b68187793b42bba3b4f65aa342f540b23c9b10a6  postgresql-15.5.tar.bz2
+# From https://ftp.postgresql.org/pub/source/v15.6/postgresql-15.6.tar.bz2.sha256
+sha256  8455146ed9c69c93a57de954aead0302cafad035c2b242175d6aa1e17ebcb2fb  postgresql-15.6.tar.bz2
 # License file, Locally calculated
-sha256  1a7d13c3ab31961b91ba256f77d6e82e0b54bf992253060fe93bdb5466df416a  COPYRIGHT
+sha256  9bf20ee493926a7e17a74bc7f05089fbc014269667b1540bc35a6b194a40c9de  COPYRIGHT

package/postgresql/postgresql.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-POSTGRESQL_VERSION = 15.5
+POSTGRESQL_VERSION = 15.6
 POSTGRESQL_SOURCE = postgresql-$(POSTGRESQL_VERSION).tar.bz2
 POSTGRESQL_SITE = https://ftp.postgresql.org/pub/source/v$(POSTGRESQL_VERSION)
 POSTGRESQL_LICENSE = PostgreSQL