Add more changelog

Signed-off-by: Pavol Loffay <[email protected]>

Author: pavolloffay

.chloggen/v1beta1-webhook.yaml

@@ -19,3 +19,7 @@ subtext: |
   Follow [migration guide](https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definition-versioning/#upgrade-existing-objects-to-a-new-stored-version) for upgrading already created collector instances.
   After all `otelcol.v1alpha1.opentelemetry.io` are stored as `v1beta1` update the collector CRD to store only `v1beta1`
   `kubectl patch customresourcedefinitions opentelemetrycollectors.opentelemetry.io  --subresource='status' --type='merge' -p '{"status":{"storedVersions":["v1beta1"]}}'`.
+  **Only `AllNamespaces` install mode is now supported** due to the conversion webhook from `v1beta1` to `v1alpha1`.
+  See [OLM docs](https://olm.operatorframework.io/docs/tasks/install-operator-with-olm/) and
+  [OLM operator groups docs](https://olm.operatorframework.io/docs/advanced-tasks/operator-scoping-with-operatorgroups/).
+