Update libyaml to 0.2.5
Update libyaml to 0.2.5

Bump libyaml version from 0.1.7 to 0.2.5.

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

Changelog: other

gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab