Update Freeswitch version to 1.4.23

Older versions have a security vulnerability https://packetstormsecurity.com/files/133781/freeswitch-Heap-Overflow.html

install/ubuntu/install_fusionpbx.sh

@@ -83,8 +83,8 @@ FSGIT=https://freeswitch.org/stash/scm/fs/freeswitch.git
 
 FSSTABLE=true
 #FSSTABLE=file
-FSStableVer="tags/v1.4.19"
-#FSStablefile=freeswitch-1.4.20
+FSStableVer="tags/v1.4.23"
+#FSStablefile=freeswitch-1.4.23
 
 FSDB=p