fix: enable compilation on JDK 21

pom.xml

@@ -30,23 +30,13 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 
-<<<<<<< Updated upstream
-    <version.java>1.8</version.java>
+    <version.java>18</version.java>
     <version.assertj>3.25.3</version.assertj>
     <version.commons.lang3>3.14.0</version.commons.lang3>
     <version.fasterxml>2.14.3</version.fasterxml>
     <version.github.mmazi>3.0</version.github.mmazi>
     <version.resilience4j>1.7.1</version.resilience4j>
     <version.junit>5.10.2</version.junit>
-=======
-    <version.java>8</version.java>
-    <version.assertj>3.24.2</version.assertj>
-    <version.commons.lang3>3.14.0</version.commons.lang3>
-    <version.fasterxml>2.14.3</version.fasterxml>
-    <version.github.mmazi>3.0</version.github.mmazi>
-    <version.resilience4j>1.7.0</version.resilience4j>
-    <version.junit>5.9.3</version.junit>
->>>>>>> Stashed changes
     <version.lombok>1.18.32</version.lombok>
     <version.knowm.xchart>3.8.6</version.knowm.xchart>
     <version.qos.logback>1.4.12</version.qos.logback>