Explicitly enable annotation processing with -proc:full.

This fixes the warning below, which is the result of an upcoming Java
change.

    Annotation processing is enabled because one or more processors were found
    on the class path. A future release of javac may disable annotation processing
    unless at least one processor is specified by name (-processor), or a search
    path is specified (--processor-path, --processor-module-path), or annotation
    processing is enabled explicitly (-proc:only, -proc:full).
    Use -Xlint:-options to suppress this message.
    Use -proc:none to disable annotation processing.

pom.xml

@@ -170,6 +170,12 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <configuration>
+                    <!--
+                        Explicitly enable annotation processing.
+                        https://inside.java/2023/07/29/quality-heads-up/
+                        https://github.com/quarkusio/quarkus/issues/37532
+                    -->
+                    <compilerArgument>-proc:full</compilerArgument>
                     <parameters>${maven.compiler.parameters}</parameters>
                 </configuration>
             </plugin>