Reset release notes (frequenz-floss#84)

Author: Marenz

RELEASE_NOTES.md

@@ -2,11 +2,7 @@
 
 ## Summary
 
-* Updates lots of dependencies and through those gets a few new features:
- * `start_immediately` when creating dispatches is now supported.
- * `http2 keepalive` is now supported and enabled by default.
- * Some bugfixes from the channels & sdk libraries. are now included.
-
+<!-- Here goes a general summary of what this release is about -->
 
 ## Upgrading
 
@@ -18,5 +14,4 @@
 
 ## Bug Fixes
 
-* Fixed a crash in the `DispatchManagingActor` when dispatches shared an equal start time.
 * Fixed a crash when reading a Dispatch with frequency YEARLY.