tools/pr_check: add Update keywork to need squashing check
tools/pr_check: add Update keywork to need squashing check

kYc0o/RIOT,kYc0o/RIOT,miri64/RIOT,kaspar030/RIOT,ant9000/RIOT,miri64/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,miri64/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,kYc0o/RIOT,kaspar030/RIOT,OlegHahm/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,miri64/RIOT,OlegHahm/RIOT,jasonatran/RIOT,kaspar030/RIOT,ant9000/RIOT,ant9000/RIOT,miri64/RIOT,ant9000/RIOT,ant9000/RIOT,jasonatran/RIOT,kYc0o/RIOT,kaspar030/RIOT,kYc0o/RIOT