Revert "Bump all managed versions preemptively"

Actually, we do not need release versions at all to make projects
benefit from the new and shiny dev profiles! We only need to bump
their parent POMs, as pointed out by Curtis Rueden...

This reverts commit a2214cebcb40975813623f022bb7dbd0b2a7acfa.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>