Can't change build environment to `local` using `skaffold inspect build-env add`

[j-windsor]

Expected behavior

skaffold inspect build-env add local is a command, as all other build environments are supported here.

Actual behavior

skaffold inspect build-env add local is not a command

Information

• Skaffold version: 1.25.0
• Operating system: macOS 11.4
• Installed via: skaffold.dev

Steps to reproduce the behavior

1. skaffold inspect build-env add local

[gsquared94]

fixed in #5944