lang-golang.rst: Remove mentioning of Go 2.0

[marcofeltmann]

As officially announced in 2023, Go 2.0 will never ever be released.

To prevent us and the Google Go team from questions like "when will Go 2.0 come?" as it was again this year at GopherConEU2024b, please remove the mention:

This may change, once go 2.0 is released.

I'd remove and PR it if I had an opinion about how to update this.

• Just drop it?
• Update with a link like

As `Go 2.0 never comes <https://go.dev/blog/compat>` this stays true for all eternity!