The docker-compose CLI v2 uses the docker/compose-go package for
parsing Docker Compose YAML specification files and currently it misses
support for the SELinux relabeling with :z or :Z.

It is a regression compared to docker-compose CLI v1 that written in Python.

I have created a Pull Request that allows to use the SELinux field to set the :z or :Z bind option for relabeling SELinux label.

References:
-Configure the selinux label