build: set the release version to v1.19.4

For the patch release update the docs and images to
v1.19.4

Signed-off-by: Michael Adam <obnox@samba.org>

Documentation/Getting-Started/quickstart.md

@@ -36,7 +36,7 @@ To configure the Ceph storage cluster, at least one of these local storage optio
 A simple Rook cluster is created for Kubernetes with the following `kubectl` commands and [example manifests](https://github.com/rook/rook/blob/master/deploy/examples).
 
 ```console
-$ git clone --single-branch --branch v1.19.3 https://github.com/rook/rook.git
+$ git clone --single-branch --branch v1.19.4 https://github.com/rook/rook.git
 cd rook/deploy/examples
 kubectl create -f crds.yaml -f common.yaml -f csi-operator.yaml -f operator.yaml
 kubectl create -f cluster.yaml