Changing the scala version for scala-maven-plugin

Since version 2.7 of the plugin, the scala version to use is detected from dependency to scala-library. So it suggested to not use scalaVersion configuration. But if you want to define explicitly the version of scala used to compile,... use 'scalaVersion', ex:

          
      <plugin>
        <groupId>net.alchim31.maven</groupId>
        <artifactId>scala-maven-plugin</artifactId>
        <version>3.2.1</version>
        <executions>
          <execution>
            <goals>
              <goal>compile</goal>
              <goal>testCompile</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <scalaVersion>${scala.version}</scalaVersion>
        </configuration>
      </plugin>