vitexsoftware backports used

only easy way ho to get current composer

ubuntu:focal/Dockerfile

@@ -5,7 +5,7 @@ ENV LC_ALL en_US.utf-8
 ENV LANG en_US.utf8
 ENV LANGUAGE=en
 
-RUN apt-get update ; apt-get install -y wget ; echo "deb [signed-by=/usr/share/keyrings/vitexsoftware.gpg] http://repo.vitexsoftware.com focal main" | tee /etc/apt/sources.list.d/vitexsoftware.list ; wget -O /usr/share/keyrings/vitexsoftware.gpg http://repo.vitexsoftware.com/keyring.gpg
+RUN apt-get update ; apt-get install -y wget ; echo "deb [signed-by=/usr/share/keyrings/vitexsoftware.gpg] http://repo.vitexsoftware.com focal main backports" | tee /etc/apt/sources.list.d/vitexsoftware.list ; wget -O /usr/share/keyrings/vitexsoftware.gpg http://repo.vitexsoftware.com/keyring.gpg
 RUN apt-get -y install locales locales-all && rm -rf /var/lib/apt/lists/* && localedef -i en_US -c -f UTF-8 -A /usr/share/locale/locale.alias en_US.UTF-8 && echo "LC_ALL=en_US.UTF-8" >> /etc/environment ; echo "en_US.UTF-8 UTF-8" >> /etc/locale.gen ; echo "LANG=en_US.UTF-8" > /etc/locale.conf ; locale-gen en_US.UTF-8 cs_CZ.UTF-8
 RUN apt-get update && apt-get install -y pbuilder sudo curl wget php composer lsb-release jq moreutils aptitude gdebi-core apt-utils apt-utils debhelper po-debconf