Release Notes; upgrade information mainly.
Features/major bugfixes are listed in NEWS

repoman-2.3.0_rc1
==================================
* Initial test release
* Bug Fixes:
    - Bug 579460 Disable the $ID header check
    - Bug 546010 Handle removed packages in vcs_files_to_cps
    - Bug 581594 Fix commit 8e7971169c2 missing self in func() parameters
    - Bug 581598 Add InvalidPackageName exception trap
    - Bug 405017 Fix copyright update
* Includes the stage2 re-writes, the checks are now in a modular system
  which is not yet fully plug-in capable.  Becoming fully plug-in capable and
  configurable is to be done in the stage3 rewites.