fix(docker-compose): service validity check

lib/manager/docker-compose/extract.ts

@@ -66,7 +66,7 @@ export function extractPackageFile(
     // Image name/tags for services are only eligible for update if they don't
     // use variables and if the image is not built locally
     const deps = Object.values(config.services || {})
-      .filter(service => service.image && !service.build)
+      .filter(service => service && service.image && !service.build)
       .map(service => {
         const dep = getDep(service.image);
         const lineNumber = lineMapper.pluckLineNumber(service.image);