It looks you didn't read the documentation cause the plugin needs to be configured correctly like this which is the generate-sources life-cycle phase and afterwards the source files which have been generated will automatically be picked up by the maven-compiler-plugin.
<build>
<plugins>
<plugin>
<groupId>org.projectlombok</groupId>
<artifactId>lombok-maven-plugin</artifactId>
<version>0.11.6.0</version>
<executions>
<execution>
<phase>generate-sources</phase>
<goals>
<goal>delombok</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>