community/rtpengine: rebuild against libwebsockets.so.19

ref #13173

community/rtpengine/APKBUILD

 # Maintainer: Leonardo Arena <rnalrd@alpinelinux.org>
 pkgname=rtpengine
 pkgver=9.3.1.2
-pkgrel=2
+pkgrel=3
 pkgdesc="Proxy for RTP traffic and other UDP based media traffic"
 url="https://github.com/sipwise/rtpengine"
 arch="all"