Update README for 5.4.0

Author: theigl

README.md

@@ -88,6 +88,7 @@ Please use the [Kryo mailing list](https://groups.google.com/forum/#!forum/kryo-
 
 ## Recent releases
 
+* [5.4.0](https://github.com/EsotericSoftware/kryo/releases/tag/kryo-parent-5.4.0) - brings bug fixes and performance improvements.
 * [5.3.0](https://github.com/EsotericSoftware/kryo/releases/tag/kryo-parent-5.3.0) - brings bug fixes and performance improvements.
 * [5.2.1](https://github.com/EsotericSoftware/kryo/releases/tag/kryo-parent-5.2.1) - brings minor bug fixes and improvements.
 * [5.2.0](https://github.com/EsotericSoftware/kryo/releases/tag/kryo-parent-5.2.0) - brings bug fixes for `RecordSerializer` and improvements. Important: If you are currently storing serialized `java.util.Record`, please see the [release notes](https://github.com/EsotericSoftware/kryo/releases/tag/kryo-parent-5.2.0) for upgrade instructions.
@@ -111,7 +112,7 @@ To use the latest Kryo release in your application, use this dependency entry in
 <dependency>
    <groupId>com.esotericsoftware</groupId>
    <artifactId>kryo</artifactId>
-   <version>5.3.0</version>
+   <version>5.4.0</version>
 </dependency>
 ```
 
@@ -121,7 +122,7 @@ To use the latest Kryo release in a library you want to publish, use this depend
 <dependency>
    <groupId>com.esotericsoftware.kryo</groupId>
    <artifactId>kryo5</artifactId>
-   <version>5.3.0</version>
+   <version>5.4.0</version>
 </dependency>
 ```
 
@@ -138,13 +139,13 @@ To use the latest Kryo snapshot, use:
 <dependency>
    <groupId>com.esotericsoftware</groupId>
    <artifactId>kryo</artifactId>
-   <version>5.3.1-SNAPSHOT</version>
+   <version>5.4.1-SNAPSHOT</version>
 </dependency>
 <!-- for usage in a library that should be published: -->
 <dependency>
    <groupId>com.esotericsoftware.kryo</groupId>
    <artifactId>kryo5</artifactId>
-   <version>5.3.1-SNAPSHOT</version>
+   <version>5.4.1-SNAPSHOT</version>
 </dependency>
 ```