Add go/buildkit redirect

This URL will be used in the docker cli to direct users to
instructions on enabling buildkit.

With this PR, https://docs.docker.com/go/buildkit/ will redirect
to https://docs.docker.com/develop/develop-images/build_enhancements/#to-enable-buildkit-builds

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

go/buildkit.md

@@ -0,0 +1,6 @@
+---
+title: How to enable BuildKit
+description: Instructions on enabling BuildKit
+keywords: BuildKit, docker build, configuration
+redirect_to: /develop/develop-images/build_enhancements/#to-enable-buildkit-builds
+---