Upgraded Firefox to version 68.0.r0.

Author: jlesage

Dockerfile

@@ -8,7 +8,7 @@
 FROM jlesage/baseimage-gui:alpine-3.9-v3.5.2
 
 # Define software versions.
-ARG FIREFOX_VERSION=67.0.4-r0
+ARG FIREFOX_VERSION=68.0-r0
 ARG JSONLZ4_VERSION=c4305b8
 ARG LZ4_VERSION=1.8.1.2
 #ARG PROFILE_CLEANER_VERSION=2.36