Redacted version and scm version, but only when `go get`ing

`buildifier --version` returns
```
buildifier version: redacted
buildifier scm revision: redacted
```

when `buildifier` is installed via `go get`, but it returns
```
buildifier version: 3.0.0
buildifier scm revision: dbd4ef8997abb3a7bef0ba4867caaf206db86b6e
```
when downloaded from github's assets in the release page.

Why is this?

Start by running `buildifier --version` for a `go get` installation and for the GitHub release asset, then compare the build paths and metadata used by each. Determine why the two commands report different version and SCM revision values, and make the output consistent or document the intended behavior.

Written by the indexing model from the issue text.