Update packaging.md for Ubuntu package building

[pimvh]

Hi! I've tried building a package on Ubuntu Jammy Jellyfish with the command specified in this docs (with sudo, as my user was not in the docker group). I ran into the following issue however (nearing the end of the build):

....
....
....
Successfully tagged ubuntu-pkgs-make:jammy
docker \
        run --rm --pid=host --network=host --privileged -v /etc/os-release:/etc/os-release-host:ro -v /home/superpim/tracee:/tracee/tracee -v /lib/modules:/lib/modules:ro -v /usr/src:/usr/src:ro -v /sys/kernel/security:/sys/kernel/security:ro -e LIBBPFGO_OSRELEASE_FILE=/etc/os-release-host \
        -it ubuntu-pkgs-make:jammy \
        packaging/ubuntu-pkgs.sh bin jammy


fatal: detected dubious ownership in repository at '/tracee/tracee'
To add an exception for this directory, call:

        git config --global --add safe.directory /tracee/tracee
dpkg-buildpackage: warning:     debian/changelog(l1): version '~22.04~2306141456-' is invalid: revision cannot be empty
LINE: tracee (~22.04~2306141456-) jammy; urgency=medium
dpkg-buildpackage: info: source package tracee
dpkg-buildpackage: info: source version unknown
dpkg-buildpackage: error: version number does not start with digit
mv: cannot stat '../*.deb': No such file or directory
rm .ubuntu-pkgs-prepare-jammy .check_docker

Seems to be a permission issue.

I think adding this or something similar to the docs could be beneficial for the read-and-run documentation readers.

1. Explain what the PR does

It adds a little bit to the Ubuntu installation docs, to make this issue avoidable for other people.

2. Explain how to test it

You can run the commands to build a package on a Ubuntu machine, on which your user is not part of the docker group (you will have to sudo make ..., and if you did not clone the repo as root, you will get this issue.

[CLAassistant]

All committers have signed the CLA.

[rafaeldtinoco]

Thanks for the contribution.