Clang binaries not releasing for ARM Ubuntu 20.04

Currently in the latest tag (v6), we do not release binaries for ARM Ubuntu 20.04.
https://github.com/nebulastream/clang-binaries/releases/tag/v6

However, it is needed and causing problems:
e.g. https://github.com/nebulastream/nebulastream/actions/runs/11675190566/job/32516310889