Add v3.16.9 to CHANGELOG.md.

[ci skip]

Author: Robert Jackson

CHANGELOG.md

@@ -77,6 +77,14 @@
 - [#18694](https://github.com/emberjs/ember.js/pull/18694) [BUGFIX] Ensure tag updates are buffered, remove error message
 - [#18709](https://github.com/emberjs/ember.js/pull/18709) [BUGFIX] Fix `this` in `@tracked` initializer
 
+### v3.16.9 (July 29, 2020)
+
+- [#19001](https://github.com/emberjs/ember.js/pull/19001) [BUGFIX] Invoke methods correctly in `TextSupport` `sendAction`
+- [#19023](https://github.com/emberjs/ember.js/pull/19023) [BUGFIX] Avoid over eager property access during `init`
+- [#19048](https://github.com/emberjs/ember.js/pull/19048) [BUGFIX] Update `router.js` to ensure `transition.abort` works for query param only transitions
+- [#19057](https://github.com/emberjs/ember.js/pull/19057) [BUGFIX] Parallelize `inject-babel-helpers` plugin
+- [#19059](https://github.com/emberjs/ember.js/pull/19059) [BUGFIX] Prevent `<base target="_parent">` from erroring in HistoryLocation
+
 ### v3.16.8 (April 24, 2020)
 
 - [#18879](https://github.com/emberjs/ember.js/pull/18879) Ensure errors thrown during component construction do not cause (unrelated) errors during application teardown (fixes a common issue when using `setupOnerror` with components asserting during `constructor`/`init`/`didInssertElement`).