Change OSM sidecar charms charmcraft.yaml

OSM sidecar charms charmcraft.yaml is changed to indicate base 20.04.

Change-Id: Ibfb5a6cd02b0025075f4109532b70c0bd6796e21
Signed-off-by: aticig <gulsum.atici@canonical.com>
diff --git a/installers/charm/juju-simplestreams-operator/charmcraft.yaml b/installers/charm/juju-simplestreams-operator/charmcraft.yaml
index 05960ce..f8944c5 100644
--- a/installers/charm/juju-simplestreams-operator/charmcraft.yaml
+++ b/installers/charm/juju-simplestreams-operator/charmcraft.yaml
@@ -23,10 +23,10 @@
 bases:
   - build-on:
       - name: "ubuntu"
-        channel: "22.04"
+        channel: "20.04"
     run-on:
       - name: "ubuntu"
-        channel: "22.04"
+        channel: "20.04"
 
 parts:
   charm: