Feedback from davidino

[avivace]

Some feedback from @dcasella

• [ ] ! -n -> -z if [ ! -n "$FONT_VERSION" ]; then can be if [ -z "$FONT_VERSION" ]; then so you can remove the !

• [ ] decide to use [ or test for every if statemant

if ! test -f "/build/private-build-plans.toml"; then -> if [ ! -f '/build/private-build-plans.toml' ]; then

• [ ] recheck the parsing of the curl output