Fix freeswitch issue with demo mode

BigBlueButton.sh

@@ -23,6 +23,8 @@ HOSTNAME=bbb.foo.bar
 # Basic setup
 apt-get install --no-install-recommends language-pack-en certbot wget equivs apt-transport-https software-properties-common python3-certbot-nginx apache2-utils
 
+update-locale LANG=en_US.UTF-8
+
 # We don't want to install ttf-mscorefonts, they are not free
 cat << EOF > bbb-fakedepends.control
 Section: misc
@@ -97,7 +99,7 @@ sed 's/http/https/' -i /var/lib/tomcat7/webapps/demo/bbb_api_conf.jsp
 sed 's/JoinViaHTML5Client=false/JoinViaHTML5Client=true/' -i /usr/share/bbb-web/WEB-INF/classes/bigbluebutton.properties
 
 # Fix integration issue with Canvas
-sed 's/5,6/5,20/' -i /opt/freeswitch/conf/dialplan/default/bbb_echo_test.xml /opt/freeswitch/conf/dialplan/default/bbb_conference.xml
+sed 's/\d{5,6}/\d{5,6}|\\d{20}/' -i /opt/freeswitch/conf/dialplan/default/bbb_echo_test.xml /opt/freeswitch/conf/dialplan/default/bbb_conference.xml
 
 bbb-conf --setip $HOSTNAME
 service nginx restart