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>

deploy/examples/operator.yaml

@@ -615,7 +615,7 @@ spec:
       serviceAccountName: rook-ceph-system
       containers:
         - name: rook-ceph-operator
-          image: docker.io/rook/ceph:v1.19.3
+          image: docker.io/rook/ceph:v1.19.4
           args: ["ceph", "operator"]
           securityContext:
             runAsNonRoot: true