Require at Least PHP 7.1

[lcharette]

[lcharette]

Since PHP 7.1 is already on Security fixes only (until 1 Dec 2019), should we move on to make 7.2 our official minimum requirement ?

[lcharette]

Since PHP 7.1 is already on Security fixes only (until 1 Dec 2019), should we move on to make 7.2 our official minimum requirement ?

Since Laravel still support 7.1, let's keep it like this for now, but also keep the warning in bake recommending 7.2