Add ember-source version to deprecation document

Author: ef4

text/1101-deprecate-ember-vendor-bundles.md

@@ -3,6 +3,7 @@ stage: released
 start-date: 2025-05-13T00:00:00.000Z
 release-date:
 release-versions:
+  ember-source: 6.10.0
 teams:
   - cli
   - framework