Inside the Jail:
crontab -e- press
i - paste
0 0 * * 0 pkg upgrade -y - press
ESC - write
:xand press enter - verify you updated the crontab using
crontab -l
This way every Sunday at 00 you will run pkg upgrade -y; use 0 0 * * 1 if you prefer Monday. Use && after each command if you want to have more than one ie 0 0 * * 0 pkg upgrade -y && git pull.