README.md: make it clear that cloning is wrong
Fixes
@@ -8,7 +8,7 @@ Go packages for [Google Cloud Platform](https://cloud.google.com) services.
import "cloud.google.com/go"
```
-To install the packages on your system,
+To install the packages on your system, *do not clone the repo*. Instead use
```
$ go get -u cloud.google.com/go/...
