Claim Go 1.8.x version requirement in BUILDING.md
@@ -9,6 +9,8 @@ In first you need to setup your Go development environment. You can follow this
guideline [How to write go code](https://golang.org/doc/code.html) and at the
end you need to have `GOPATH` and `GOROOT` set in your environment.
+Current containerd requires Go 1.8.x or above.
+
At this point you can use `go` to checkout `containerd` in your `GOPATH`:
```sh
