golang.org/x/net is vendored in branch 1.5.1

[jech]

Is there an existing issue for this?

• [X] I have searched the existing issues

Current Behavior

There is a directory vendor with golang.org/x/net included.

Expected Behavior

There is no vendor directory in the library, the dependency is declared in go.mod

Steps To Reproduce

1. Type ls vendor/

Anything else?

No response