remove workaround for apptainer 1.3.0

install_apptainer_ubuntu.sh

@@ -5,11 +5,7 @@ set -e
 # see https://github.com/apptainer/singularity/issues/5390#issuecomment-899111181
 sudo apt-get install alien
 alien --version
-# stick to Apptainer < 1.3.0 by downloading from EPEL 8.8 archive,
-# since CI workflow for testing scripts hangs/fails when using Apptainer 1.3.0
-# cfr. https://github.com/EESSI/software-layer/pull/514
 epel_subdir="pub/epel/8"
-epel_subdir="pub/archive/epel/8.8"
 apptainer_rpm=$(curl --silent -L https://dl.fedoraproject.org/${epel_subdir}/Everything/x86_64/Packages/a/ | grep 'apptainer-[0-9]' | sed 's/.*\(apptainer[0-9._a-z-]*.rpm\).*/\1/g')
 curl -OL https://dl.fedoraproject.org/${epel_subdir}/Everything/x86_64/Packages/a/${apptainer_rpm}
 sudo alien -d ${apptainer_rpm}