nf-core tools in docker is broken

Description of the bug

Tools does not handle failure to create .config directory as it should. Lacking a proper $HOME it will default to / and try to create /.config

Command used and terminal output

pontus@atra:~$ docker run -itv `pwd`:`pwd` -w `pwd` -u $(id -u):$(id -g) nfcore/tools
Traceback (most recent call last):
  File "/usr/local/bin/nf-core", line 5, in <module>
    from nf_core.__main__ import run_nf_core
  File "/usr/local/lib/python3.8/site-packages/nf_core/__main__.py", line 31, in <module>
    nf_core.utils.setup_nfcore_dir()
  File "/usr/local/lib/python3.8/site-packages/nf_core/utils.py", line 310, in setup_nfcore_dir
    os.makedirs(NFCORE_DIR)
  File "/usr/local/lib/python3.8/os.py", line 213, in makedirs
    makedirs(head, exist_ok=exist_ok)
  File "/usr/local/lib/python3.8/os.py", line 223, in makedirs
    mkdir(name, mode)
PermissionError: [Errno 13] Permission denied: '/.config'
pontus@atra:~$

System information

No response

Start in nf_core/utils.py at setup_nfcore_dir(), identified in the traceback, and reproduce the provided docker run command with the shown user and missing HOME. Trace how NFCORE_DIR is derived and how directory-creation failures are handled. Done means the container no longer attempts an unauthorized /.config path and the behavior is covered by the relevant tests.