Raise YAML compliance to 1.2

The YAML 1.2 spec was released in 2009. It's probably been enough time
that it's safe to move to it.

The only issue for out YAML usage was 1.2 dropped the use of Yes, No, On,
and Off as valid boolean values.

Change-Id: I608e09d219379e00cca15c5ff165bb63aecfe9f2
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

deliverables/stein/python-troveclient.yaml

@@ -1,5 +1,5 @@
 ---
-include-pypi-link: yes
+include-pypi-link: true
 launchpad: python-troveclient
 release-model: cycle-with-intermediary
 team: trove