[post-release] Add OLM digest bundle for v0.40.0 in 0.40.x

Signed-off-by: David Kwon <dakwon@redhat.com>

Author: dkwon17

olm-catalog/release-digest/channel.yaml

@@ -55,3 +55,5 @@ entries:
     replaces: devworkspace-operator.v0.37.0
   - name: devworkspace-operator.v0.39.0
     replaces: devworkspace-operator.v0.38.0
+  - name: devworkspace-operator.v0.40.0
+    replaces: devworkspace-operator.v0.39.0