catalog-model: Deprecate entity.metadata.generation

Signed-off-by: Johan Haals <johan.haals@gmail.com>

.changeset/thirty-keys-study.md

@@ -0,0 +1,5 @@
+---
+'@backstage/catalog-model': patch
+---
+
+Deprecated the `entity.metadata.generation` field which has been superseded by `entity.metadata.etag`.

packages/catalog-model/src/entity/Entity.ts

@@ -116,6 +116,7 @@ export type EntityMeta = JsonObject & {
    * This field can not be set by the user at creation time, and the server
    * will reject an attempt to do so. The field will be populated in read
    * operations.
+   * @deprecated replaced by etag.
    */
   generation?: number;