chore(cache): improve changeset

Signed-off-by: Benjamin Janssens <benji.janssens@gmail.com>

.changeset/sour-lines-taste.md

@@ -1,5 +1,21 @@
 ---
-'@backstage/backend-defaults': patch
+'@backstage/backend-defaults': minor
 ---
 
-Improved support for Valkey
+**BREAKING** The correct configuration options for Valkey are now being used.
+
+These changes are **required** to `app-config.yaml`:
+
+```diff
+backend:
+  cache:
+    valkey:
+      client:
+-       namespace: 'my-app'
+-       keyPrefixSeparator: ':'
++       keyPrefix: 'my-app:'
+-       clearBatchSize: 1000
+-       useUnlink: false
+```
+
+In comparison to Redis, Valkey requires the full `keyPrefix` including the separator to be specified instead of separate `namespace` and `keyPrefixSeparator` options. Also, Valkey does not support the `clearBatchSize` and `useUnlink` options.