Update RELEASE_NOTES.md for 1.5.40.1 release (#532)

Author: Arkatufus

RELEASE_NOTES.md

@@ -1,6 +1,3 @@
-#### 1.5.40 March 24th 2025 ####
+#### 1.5.40.1 April 7th 2025 ####
 
-Akka.Persistence.Sql 1.5.40 contains a mission-critical bugfix from Akka 1.5.40 that fixes the [`SelectAsync` `NullReferenceException` issue](https://github.com/akkadotnet/Akka.Persistence.Sql/issues/498) 
-
-* [Bump Akka version to 1.5.40](https://github.com/akkadotnet/akka.net/releases/tag/1.5.40)
-* [Bump Akka.Hosting version to 1.5.40](https://github.com/akkadotnet/Akka.Hosting/releases/tag/1.5.40)
+* [Fix duplicate actor name for read journal sequencer actors](https://github.com/akkadotnet/Akka.Persistence.Sql/pull/531)