Update version of PyYAML

Change-Id: I2c53f1ffa67ec6cbda483e839be2778f185100a9
Signed-off-by: Mark Beierl <mark.beierl@canonical.com>
(cherry picked from commit 7aad5a5da15c7b5d6c4d87f27fc0cc59c3ce5e79)
3 files changed