As suggest by Go developers, use `filepath.WalkDir` instead of
`filepath.Walk` because [*Walk is less efficient than WalkDir,
introduced in Go 1.16, which avoids calling `os.Lstat` on every file or
directory visited](https://pkg.go.dev/path/filepath#Walk).
This proposition address that, in a similar way as
https://github.com/go-gitea/gitea/pull/22392 did.
Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
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