Update RELEASE.md to point to HEAD binaries

Author: pwittrock

RELEASE.md

@@ -9,4 +9,11 @@ The Kubebuilder Project is released on an as-needed basis. The process is as fol
 1. An announcement email is sent to `[email protected]` with the subject `[ANNOUNCE] kubebuilder $VERSION is released`
 
 Note: This process does not apply to EAP or alpha (pre-)releases which may be cut at any time for development
-and testing.
+and testing.
+
+## HEAD releases
+
+The binaries releases for HEAD are available here:
+
+- [kubebuilder-release-master-head-darwin-amd64.tar.gz](https://storage.googleapis.com/kubebuilder-release/kubebuilder-release-master-head-darwin-amd64.tar.gz)
+- [kubebuilder-release-master-head-linux-amd64.tar.gz](https://storage.googleapis.com/kubebuilder-release/kubebuilder-release-master-head-linux-amd64.tar.gz)