Reduce the level of logging when applying `McJavaPlugin`

[alexander-yevsyukov]

McJavaPlugin when applied to a project, logs the fact with the level of WARN. The level of debugging was selected intentionally to always see the version of the plugin applied to the project which was important when running integration tests.

We need to reduce the level to INFO so that we do not pollute the console with the output which is of no importance for the end user.