Clear up space on cl-root which would typically cause the alert

Filesystem Size Used Avail Use% Mounted on
/dev/mapper/cl-root 50G 31G 19G 63% /
devtmpfs 7.8G 0 7.8G 0% /dev
tmpfs 7.8G 0 7.8G 0% /dev/shm
tmpfs 7.8G 642M 7.2G 9% /run
tmpfs 7.8G 0 7.8G 0% /sys/fs/cgroup
/dev/sda1 1014M 338M 677M 34% /boot
/dev/mapper/cl-home 965G 6.2G 959G 1% /home
tmpfs 1.6G 12K 1.6G 1% /run/user/42
tmpfs 1.6G 0 1.6G 0% /run/user/0
tmpfs 1.6G 0 1.6G 0% /run/user/1000