CHANGELOG.md: add CRD file name and error cases changes

Author: estroz

CHANGELOG.md

@@ -26,6 +26,8 @@
 - Upgrade [`controller-runtime`](https://github.com/kubernetes-sigs/controller-runtime) version from `v0.1.12` to `v0.2.0-beta.3`
 - Upgrade Kubernetes version from `kubernetes-1.13.4` to `kubernetes-1.14.1`
 - Upgrade `github.com/operator-framework/operator-lifecycle-manager` version from `b8a4faf68e36feb6d99a6aec623b405e587b17b1` to `0.10.1`
+- CRD file names were previously of the form `<group>_<version>_<kind>_crd.yaml`. Now that CRD manifest `spec.version` is deprecated in favor of `spec.versions`, i.e. multiple versions can be specified in one CRD, CRD file names have the form `<group>_<resource>_crd.yaml`. `<resource>` is the plural lower-case CRD Kind found at `spec.names.plural`.
+- CRD manifest `spec.version` is still supported, but users will see a warning message if `spec.versions` is not present and an error if `spec.versions` is populated but the version in `spec.version` is not in `spec.versions`.
 
 ### Breaking changes