[VOL-5257] Release repo:voltha-openolt-adaptert

VERSION
.gitreview
----------
 o Post release tag & branch patch for branch=voltha-2.12
 o Bump version string to avoid conflicts:
   - branch=master  (X.{1+Y}.0)
   - branch=release (X.Y.{1+Z})
 o Update .gitreview (defaultpath=voltha-2.12), specify rebase/merge target.

    Update docs.voltha.org release version matrix.

howot/release/repositories/
  o Document more caveats for releasing indivdiual repositories.
  o repo:ci-management must be released twice:
    - first to establish a branhc for pipeline jobs.
    - second to update dependent versions after downstream repos have been released

Change-Id: I90d2773dd63836366ba92d7e501ec46e12e92851
diff --git a/.gitreview b/.gitreview
index a81beda..24d3f54 100644
--- a/.gitreview
+++ b/.gitreview
@@ -2,4 +2,4 @@
 host=gerrit.opencord.org
 port=29418
 project=voltha-openolt-adapter.git
-defaultremote=master
+defaultremote=voltha-2.12