[VOL-5009] - Update release notes

[VOL-5061]

overview/releases.rst
---------------------
  o Correct start/end release dates for v2.10-v2.12 to reflect reality.

release_notes/voltha_2.12.rst
-----------------------------
  o Populate the onos apps grid with versioned artifact and VCS urls.
  o Component kafka the only holdout

howto/release/checklist.rst
howto/release/components/index.rst
howto/release/index.rst
howto/release/voltha-docs/index.rst
howto/release/voltha-docs/release_notes.rst
howto/release/branching/
howto/release/components/igmpproxy/
howto/release/components/kafka/
howto/release/components/maclearner/
howto/release/components/pppoeagent/
howto/release/voltha-docs/release_history.rst
---------------------------------------------
  o Add more random content and links for release dependencies and tasks.

Change-Id: I31338488a4e626a97435429a36e200d54cf6267e
diff --git a/howto/release/release-notes.rst b/howto/release/release-notes.rst
index 6e762dc..c9f1c23 100644
--- a/howto/release/release-notes.rst
+++ b/howto/release/release-notes.rst
@@ -28,7 +28,7 @@
 
 - Add `release_notes/voltha_2.12.rst <https://gerrit.opencord.org/plugins/gitiles/voltha-docs/+/refs/heads/master/release_notes/voltha_2.11.rst>`_ in the index file `release_notes/index.rst <https://gerrit.opencord.org/plugins/gitiles/voltha-docs/+/refs/heads/master/release_notes/index.rst>`_
 
-- Modify `config.py <https://gerrit.opencord.org/plugins/gitiles/voltha-docs/+/refs/heads/master/conf.py#308>`_ so ``make linkcheck`` will not fail on yet-to-be-generated html release notes file.
+- Modify `config.py <https://gerrit.opencord.org/plugins/gitiles/voltha-docs/+/refs/heads/master/conf.py>`_ so ``make linkcheck`` will not fail on yet-to-be-generated html release notes file.
 
 - Release notes: content and hilights: