experimental/firefox-esr: bump for llvm8

experimental/firefox-esr/APKBUILD

 # Maintainer: A. Wilcox <awilfox@adelielinux.org>
 pkgname=firefox-esr
 pkgver=60.6.1
-pkgrel=0
+pkgrel=1
 pkgdesc="Firefox web browser"
 url="https://www.mozilla.org/en-US/firefox/organizations/faq/"
 arch="all"
@@ -15,7 +15,7 @@ depends_dev="alsa-lib-dev bzip2-dev dbus-glib-dev gconf-dev gtk+2.0-dev
 	pulseaudio-dev sqlite-dev startup-notification-dev wireless-tools-dev"
 makedepends="$depends_dev autoconf2.13 automake libtool
 	bsd-compat-headers cmd:which nss-static openssl-dev sed yasm zip
-	cargo clang llvm7-dev rust"
+	cargo clang llvm8-dev rust"
 subpackages=""
 _py2ver=2.7.15
 source="https://ftp.mozilla.org/pub/firefox/releases/${pkgver}esr/source/firefox-${pkgver}esr.source.tar.xz