Revert "Updated compiler target version"

This reverts commit 4a303c1.

Author: josemmo

pom.xml

@@ -9,7 +9,8 @@
     <version>1.3.0-SNAPSHOT</version>
 
     <properties>
-        <maven.compiler.release>9</maven.compiler.release>
+        <maven.compiler.source>8</maven.compiler.source>
+        <maven.compiler.target>8</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>