Now support more possible version strings from the peer,
in case of future changes:
* 4-component versions (2.1.3.1)
* <3-component versions (10 or 10.1), in case we want to provide
  less details to the peer about our version in the future.

Also cleanup to use string-view (2 less string allocations).

Change-Id: Ifbd35d203a47fc573b4670218ce4ccc9bebaecc5