Update readme for release (#106)

Author: Marenz

RELEASE_NOTES.md

@@ -5,7 +5,3 @@
 * Update BaseApiClient to get the http2 keepalive feature.
 * Some Methods from the high-level API have been moved to this repo: The dispatch class now offers: `until`, `started`, `next_run` and `next_run_after`.
 * Add `start_immediately` support to the `create` method. You can now specify "NOW" as the start time to trigger immediate dispatch. Note: While the dispatch CLI previously allowed this by converting "NOW" to a timestamp client-side before sending it to the server, this functionality is now supported directly on the server side!
-
-## Bug Fixes
-
-* Fix crash by adding the missing YEARLY frequency.