Update Go parser with generics support

[mark-pictor-csec]

The go parser astexplorer uses reports a version of 1.13.4; if that's a go version, it is very dated. The latest version of golang is 1.21 - see go.dev/dl.

It'd be nice to see astexplorer's go parser updated so people can use it on code with generics, the any keyword, etc.