Remove 'version' from ComposeService. 'version' key in Compose was de…

…precated for a while, but now it also throws an annoying WARN[0000] version is obsolete

lib/factory.js

@@ -13,7 +13,7 @@ const dockerCompose = class ComposeService {
   constructor(id, info = {}, ...sources) {
     this.id = id;
     this.info = info;
-    this.data = _(sources).map(source => _.merge({}, source, {version: '3.6'})).value();
+    this.data = _(sources).map(source => _.merge({}, source, {})).value();
   };
 };