Drop support for old versions of Go

[johnweldon]

When updating dependencies to address vulnerabilities we're running into updated dependencies only supporting recent versions of Go (#553)

How much of an impact would it be to drop support of Go versions prior to 1.23? (In keeping with the Go maintainers own support policy)

[cpuschma]

I don't think it would be a great loss if we stopped supporting older Go versions and stuck to the Go release and support cycle with two active versions

At the end of the day, it's extra work for us (in the past we had to consider sensitivities) and we can't guarantee that retroactive changes from the Go stdlib won't affect older versions anyway

[cpuschma]

Let us support the two latest versions in parallel with the Go Team. We do not lose any retroactive compatibility with the change and can extend the scope again at any time.