.github: use ubuntu-16.04 to run linux actions
.github: use ubuntu-16.04 to run linux actions

galek/crown,mikymod/crown,mikymod/crown,dbartolini/crown,dbartolini/crown,dbartolini/crown,mikymod/crown,galek/crown,galek/crown,mikymod/crown,galek/crown,dbartolini/crown