chore: set compiler version to 8

Author: muehre

pom.xml

@@ -53,6 +53,14 @@
                     </filters>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 
@@ -85,4 +93,7 @@
             <scope>compile</scope>
         </dependency>
     </dependencies>
+
+    <properties>
+    </properties>
 </project>