Add ghcr.io to list of mirrors in install_k3s_cluster.sh

Change-Id: I7a3823f3fc245f27d350712afb7c760aeefa07d7
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/installers/cluster/k3s/install_k3s_cluster.sh b/installers/cluster/k3s/install_k3s_cluster.sh
index 0368b64..670de0b 100755
--- a/installers/cluster/k3s/install_k3s_cluster.sh
+++ b/installers/cluster/k3s/install_k3s_cluster.sh
@@ -26,6 +26,9 @@
         sudo mkdir -p /etc/rancher/k3s/
         cat << EOF | sudo tee /etc/rancher/k3s/registries.yaml > /dev/null
 mirrors:
+  ghcr.io:
+    endpoint:
+      - "${DOCKER_PROXY_URL}"
   docker.io:
     endpoint:
       - "${DOCKER_PROXY_URL}"