assume yes on apt install and reduce verbosity

Related: #14
Signed-off-by: Daniel Andrei Minca <mandrei17@gmail.com>

build.sh

 #!/bin/bash
 
 # Install dependencies (debbootstrap)
-sudo apt-get install debootstrap curl
+sudo apt-get install -yqq debootstrap curl
 
 # -----------------------------------------------------------------------------
 # BUILD/LABEL VARIABLES