proposal: go get -u should inform about new major versions

[firefart]

Proposal Details

It would be great if the go get -u command could print an info message if there is a new major version of a package available.
Currently you need to check the packages one by one to see if there is a new v3 version while you are still running on v2 for example.

Example:
This example is even more complex because the repo was renamed between v8 and v9 (github.com/go-redis/redis/v8 to github.com/redis/go-redis/v9):
Suppose you are running a project that referencs redis v8. It would be really helpful to print a message saying "Hey, there is already a v9 available, you might want to consider upgrading". This can also prevent bugs like autoimport importing redis v1 where you really wanted the latest version. In this case the message could also hint at some errors.

[fzipp]

Duplicate of #40323

[firefart]

sorry didnt find that one