Because you want to make changes on a storage device, you are asked to enter your password. You can add your user to the group: disk to avoid this.
who or whoami - my login-name
id - more details
groups - all your groups
less /etc/group | grep disk - focus on disk
Add an existing user to another group, like this:
sudo usermod -aG disk LOGIN-NAMEI saw my entry not immediately check it with: cat /etc/group
Under releases http://gitlab.com/bztsrc/usbimager you may find your preferred pre built binary, if not, I recommend this link http://gitlab.com/bztsrc/usbimager/tree/binaries