pom.xml: When using slf4j, make sure we don't accidentally depend on commons-logging

pom.xml

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-enforcer-plugin</artifactId>
        <executions>
          <execution>
            <id>ban-unwanted-dependencies</id>
            <goals>
              <goal>enforce</goal>
            </goals>
            <configuration>
              <rules>
                <!-- documentation at: https://maven.apache.org/enforcer/enforcer-rules/index.html -->
                <bannedDependencies>
                  <excludes>
                    <exclude>commons-logging:commons-logging</exclude> <!-- use jcl-over-slf4j instead -->
                  </excludes>
                </bannedDependencies>
              </rules>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>