[POM] There is no need to require java 13

pom.xml

@@ -21,7 +21,7 @@
     </dependencies>
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <maven.compiler.source>13</maven.compiler.source>
-        <maven.compiler.target>13</maven.compiler.target>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
     </properties>
-</project>
\ No newline at end of file
+</project>