Pin version of LXD to latest LTS, juju 2.8.11 and microk8s 1.20

Change-Id: I31f5540e0d8991006e8b3767a94fe4126945cafb
Signed-off-by: David Garcia <david.garcia@canonical.com>
diff --git a/installers/charmed_install.sh b/installers/charmed_install.sh
index 3703ca6..c2a3a31 100755
--- a/installers/charmed_install.sh
+++ b/installers/charmed_install.sh
@@ -15,12 +15,12 @@
 
 # set -eux
 
-LXD_VERSION=4.17
+LXD_VERSION=4.0
 JUJU_VERSION=2.8
-JUJU_AGENT_VERSION=2.8.9
+JUJU_AGENT_VERSION=2.8.11
 K8S_CLOUD_NAME="k8s-cloud"
 KUBECTL="microk8s.kubectl"
-MICROK8S_VERSION=1.19
+MICROK8S_VERSION=1.20
 OSMCLIENT_VERSION=10.0
 IMAGES_OVERLAY_FILE=~/.osm/images-overlay.yaml
 PATH=/snap/bin:${PATH}