Merge pull request #42 from mnottale/yaml-omitempty

vendor update: 'omitempty' yaml tag for compose struct.

Author: mat007

Gopkg.lock

@@ -6,7 +6,3 @@ services:
     - -c
     - cat bar bam
     image: alpine:latest
-networks: {}
-volumes: {}
-secrets: {}
-configs: {}

e2e/render/envvariables.dockerapp/expected.txt

@@ -10,7 +10,3 @@ services:
     image: alpine:latest
   other:
     image: nginx
-networks: {}
-volumes: {}
-secrets: {}
-configs: {}