chore: increase version in pom manually

Author: fabianbormann

pom.xml

@@ -11,7 +11,7 @@
 
   <groupId>org.cardanofoundation</groupId>
   <artifactId>rewards</artifactId>
-  <version>0.3.0</version>
+  <version>0.4.0</version>
   <name>cardano-reward-calculation</name>
   <packaging>jar</packaging>
   <description>This project aims to be a cardano reward calculation, java formula implementation and edge case documentation</description>