Merge branch 'wip-deadlock' into 'master'

🐛 fix mutex deadlock

See merge request !15
7 jobs for master in 10 minutes and 57 seconds (queued for 5 seconds)
Name Stage Failure
failed
ci-git-submodules Test
Entering 'deps/ntofutils/deps/dim'
Executing "step_script" stage of the job script
Using docker image sha256:ffc09642b52962d4aea941f6cc47a81ab8a382691386bee3d43f0f5032571584 for gitlab-registry.cern.ch/ntof/daq/builder with digest gitlab-registry.cern.ch/ntof/daq/builder@sha256:1a9320331e1d72129a9de5cdcfb7dbed9349ab6440afa6e786dc18de301179dc ...
$ git submodule update --remote
Submodule path 'deps/ntofutils': checked out 'a9def332eab9ed1bf5f97dcedb5c3e3ac652f770'
$ [ $(git status -uno --porcelain | wc -l) -eq 0 ] || { echo "Please update git-submodules"; exit 1; }
Please update git-submodules
Cleaning up file based variables
ERROR: Job failed: exit code 1