Many dependencies already import gopkg.in/yaml.v2, podman is the only
user of the v3 version except github.com/stretchr/testify but this is
only a testing dependency so it will not end up in the binary.
This change reduces the podman binary size from 54740 to 54260 KB on my
system.
[NO NEW TESTS NEEDED]
Signed-off-by: Paul Holzinger <pholzing@redhat.com>
8f2f8d4cad