Add v6.4.0-beta.1 to CHANGELOG for ember-source

(cherry picked from commit bfe18a5)

Author: kategengler

CHANGELOG.md

@@ -1,5 +1,22 @@
 # Ember Changelog
 
+## v6.4.0-beta.1 (March 17, 2025)
+
+- [#20842](https://github.com/emberjs/ember.js/pull/20842) [BREAKING] Drop support for TypeScript 4.9 to allow for glimmer-vm upgrade. 
+  * Ember now tests against TypeScript 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7. 
+  Per the rolling support window, following [Semantic Versioning for TypeScript Types](https://www.semver-ts.org/),
+  the supported range of TypeScript versions across two Ember LTS releases must 
+  always overlap.
+  For more examples, see the [Stability heading in this blog post](https://blog.emberjs.com/stable-typescript-types-in-ember-5-1/).
+  * We now require consumers use `verbatimModuleSyntax`.
+- [#20842](https://github.com/emberjs/ember.js/pull/20842) / [#20864](https://github.com/emberjs/ember.js/pull/20864) Upgrade glimmer-vm.
+- [#20872](https://github.com/emberjs/ember.js/pull/20872) [BUGFIX] Fix `{{debugger}}` via upgrade @glimmer/runtime.
+- [#20850](https://github.com/emberjs/ember.js/pull/20850) [BUGFIX] Fix source maps in published packages.
+- [#20867](https://github.com/emberjs/ember.js/pull/20867) [BUGFIX] Fix LOG_VERSIONS.
+- [#20852](https://github.com/emberjs/ember.js/pull/20852) [CLEANUP] Remove ember-auto-import as a dependency.
+- [#20863](https://github.com/emberjs/ember.js/pull/20863) [CLEANUP] Cleanup "octane edition" code
+- [#20856](https://github.com/emberjs/ember.js/pull/20856) [DOCS] Restore @glimmer/component API docs and test against classes and modules generated in api docs to prevent future missing docs.
+
 ## v6.3.0 (March 17, 2025)
 
 - [#20800](https://github.com/emberjs/ember.js/pull/20800) [FEATURE] Support use of template-tag components as route templates per [RFC #1046](https://rfcs.emberjs.com/id/1046-template-tag-in-routes).