Fixing resolv.conf issue on Linux Mint

Bad news: installing a network tool broke my internet connection, because the damn thing made changes to the /etc/resolv.conf file. Good news: after some frantic research, the following commands fixed the issue.

sudo chattr -i /etc/resolv.conf
sudo rm /etc/resolv.conf
sudo ln -s /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf