utils: Walk, use os.FileInfo
utils: Walk, use os.FileInfo

fs.FileInfo has been introduced in go 1.16.5:
https://github.com/golang/go/commit/d4da735091986868015369e01c63794af9cc9b84#diff-46ea5b4a04796237678b36cd31d68f74209c90d604123f15dcc4bcb605dbc136

go-billy supports the 2 latest versions
The latest version of go is currently 1.16, hence use the previous
instance in os instead

go-git/go-billy