main/postfix: upgrade to 2.8.3

fixes #677

(cherry picked from commit 229c27e8)

main/postfix/APKBUILD

 # Maintainer: Natanael Copa <ncopa@alpinelinux.org>
 pkgname=postfix
-pkgver=2.8.2
-pkgrel=1
+pkgver=2.8.3
+pkgrel=0
 pkgdesc="Secure and fast drop-in replacement for Sendmail (MTA)"
 url="http://www.postfix.org/"
 arch="all"
@@ -152,7 +152,7 @@ pcre()  { _mv_dict pcre ; }
 pgsql() { _mv_dict pgsql ; }
 sqlite() { _mv_dict sqlite ; }
 
-md5sums="9fcc6df448b03a646a18a2dee11ca070  postfix-2.8.2.tar.gz
+md5sums="b3922ededd3fd6051f759e58a4ada3ae  postfix-2.8.3.tar.gz
 6bbabcd041aefaf40e1f3ee1fc1d6d7e  postfix.initd
 632fce950f64aa0794f9c2af85d45423  0001-support-for-dynamic-maps.patch
 442efd1a95b0c061dfb8ab75456e0f24  dynamicmaps.cf