Update dependency org.pitest:pitest-maven to v1.20.4

Author: renovate[bot]

pom.xml

@@ -137,7 +137,7 @@
       <plugin>
         <groupId>org.pitest</groupId>
         <artifactId>pitest-maven</artifactId>
-        <version>1.20.0</version>
+        <version>1.20.4</version>
         <executions>
           <execution>
             <goals>