multilmodule/index.md Maven 2.0 reference

[elharo]

Affected version

HEAD

Bug description

Is this still accurate? If so, remove "2.0". If it isn't, remove the whole paragraph.

**Note:** Because of a quirk in Maven 2.0's execution model relating to aggregator goals and the inheritance hierarchy, we need to explicitly execute the package phase ahead of the assembly invocation.
This ensures all modules have been built.

[AzazelSensei]

Opened #1371 — kept the note and dropped the 2.0 qualifier, since mvn clean package is still required for the reactor modules.