Mark specs implemented in Newton

These are completed.

Note that the OSC plugin spec and the third party CI spec aren't
necessarily tied to 6.2, however I don't have a better place to put
them, and this sufficiently communicates the timeframe they were
completed in, so I'm rolling with it.

Change-Id: If1efb7d8babb9171c508e1ad5f9fe1e95fc278f8

doc/source/index.rst

@@ -63,6 +63,15 @@ development cycles in which they were completed.
 Newton
 ------
 
+6.2
+~~~
+
+.. toctree::
+   :glob:
+   :maxdepth: 1
+
+   specs/6.2/*
+
 6.1
 ~~~