Rather than linking to recent releases by version, link to the series
docs by name. This allows us to link to a more limited number of
"versions" but maintain those links indefinitely now that we are
planning to retain our documentation online for a more extended period
of time.
The implementation uses dulwich to identify the tags and branches
rather than using git via subprocess.
Change-Id: If691b257f5fba7e431a1acd9d1a03415f2d07420
Signed-off-by: Doug Hellmann <doug@doughellmann.com>
2e8624f445