update vendor

vendor/modules.txt

@@ -15,22 +15,23 @@ github.com/docker/distribution/digestset
 # github.com/docker/docker v1.13.1 => github.com/docker/engine v0.0.0-20181106193140-f5749085e9cb
 github.com/docker/docker/api/types
 github.com/docker/docker/api/types/container
+github.com/docker/docker/api/types/filters
 github.com/docker/docker/builder/dockerignore
 github.com/docker/docker/client
 github.com/docker/docker/pkg/archive
 github.com/docker/docker/pkg/fileutils
-github.com/docker/docker/api/types/filters
+github.com/docker/docker/pkg/stdcopy
 github.com/docker/docker/api/types/mount
 github.com/docker/docker/api/types/network
 github.com/docker/docker/api/types/registry
 github.com/docker/docker/api/types/swarm
 github.com/docker/docker/api/types/blkiodev
 github.com/docker/docker/api/types/strslice
+github.com/docker/docker/api/types/versions
 github.com/docker/docker/api
 github.com/docker/docker/api/types/events
 github.com/docker/docker/api/types/image
 github.com/docker/docker/api/types/time
-github.com/docker/docker/api/types/versions
 github.com/docker/docker/api/types/volume
 github.com/docker/docker/pkg/idtools
 github.com/docker/docker/pkg/ioutils
@@ -119,6 +120,7 @@ github.com/src-d/gcfg/token
 github.com/src-d/gcfg/types
 # github.com/stretchr/testify v1.3.0
 github.com/stretchr/testify/assert
+github.com/stretchr/testify/require
 # github.com/xanzy/ssh-agent v0.2.0
 github.com/xanzy/ssh-agent
 # golang.org/x/crypto v0.0.0-20190131182504-b8fe1690c613
@@ -199,8 +201,6 @@ gopkg.in/src-d/go-git.v4/plumbing/transport/internal/common
 gopkg.in/src-d/go-git.v4/plumbing/transport/server
 # gopkg.in/warnings.v0 v0.1.2
 gopkg.in/warnings.v0
-# gopkg.in/yaml.v2 v2.2.2
-gopkg.in/yaml.v2
 # gotest.tools v2.2.0+incompatible
 gotest.tools/assert
 gotest.tools/assert/cmp