Maybe modifications with newer go version in go-post-fetch required

Dear all,

I just had a nasty bug, that `go mod download` was rewriting the go.mod 
file and was adding modification to the go.mod file:

> ❯ diff -u go.mod.orig go.mod
> --- go.mod.orig 2024-04-21 20:01:29.098380000 +0300
> +++ go.mod      2024-04-21 21:01:03.081898000 +0300
> @@ -1,6 +1,8 @@
>  module gitlab.com/gitlab-org/gitlab-shell/v14
>
> -go 1.20
> +go 1.21
> +
> +toolchain go1.22.2
>
>  require (
>         github.com/charmbracelet/git-lfs-transfer 
> v0.1.1-0.20240402115927-f0b226fa61cc 

This causes an invalid checksum, if you execute `make makesum` for a go 
package and therefor a fetch on another computer or after you deleted 
the go.mod from distfiles.

I saw this problem for devel/gitlab-shell and fixed the problem by copy 
the initial go.mod and restore it after `go mod download` was executed.
Maybe this is a new behaviour with go 1.22 and also a modification is 
maybe here required:
https://cgit.freebsd.org/ports/tree/Mk/Uses/go.mk#n188

The fix I did is here:
https://cgit.freebsd.org/ports/commit/?id=30ee39816e4e27529f1f2421820962b961c5fc0e

Gruß
Matthias

-- 

"Programming today is a race between software engineers striving to
build bigger and better idiot-proof programs, and the universe trying to
produce bigger and better idiots. So far, the universe is winning." --
Rich Cook