Suspend the CI runs on CentOS 7, which fail due to a cryptic git error
connected with checking out the libshared submodule version. Might be
just a bug that is fixed in more recent git versions, which would
explain why other CI runs work fine.
The build of the docker image currently fails due to a bug unrelated to
TW [1]. This will be reverted once the issue is fixed.
[1] https://bugs.archlinux.org/task/69563