Fixing broken link for vet

.github/CONTRIBUTING.md

@@ -24,7 +24,7 @@ We will gladly accept bug fixes, or additions to this library. Please fork this
 - If you plan to work on something major, please open an issue to discuss the design first.
 - Don't break backwards compatibility. If you really have to, open an issue to discuss this first.
 - Make sure to use the `go fmt` command to format your code according to the standards. Even better, set up your editor to do this for you when saving.
-- Run [go vet](https://godoc.org/golang.org/x/tools/cmd/vet) to detect any suspicious constructs in your code that could be bugs.
+- Run [go vet](https://golang.org/cmd/vet/) to detect any suspicious constructs in your code that could be bugs.
 - Explicitly handle all error return values. If you really want to ignore an error value, you can assign it to `_`.You can use [errcheck](https://github.com/kisielk/errcheck) to verify whether you have handled all errors.
 - You may also want to run [golint](https://github.com/golang/lint) as well to detect style problems.
 - Add tests that cover the changes you made. Make sure to run `go test` with the `-race` argument to test for race conditions.