Upgrade cortexto use go 1.20

[alanprot]

Go 1.20 was released: https://go.dev/doc/go1.20

[mehrdadbn9]

hi i would like to contribute
if i change go .mod is enough or i should do sth else as well?

[alvinlin123]

@mehrdadbn9 there is also build image that need to be upgraded like here: 5347bf4

[mehrdadbn9]

thanks for your answer
please assign me
as i understood i should change dockerfile so happy to do it