Correct execCreate() return type in docs' example
`execCreate()` returns `ExecCreation`, not a `String`
@@ -587,7 +587,7 @@ try (InputStream imagePayload = new BufferedInputStream(new FileInputStream(tarF
### Exec Create
```java
-final String execId = docker.execCreate(containerId, new String[]{"sh", "-c", "exit 2"});
+final String execId = docker.execCreate(containerId, new String[]{"sh", "-c", "exit 2"}).id();
try (final LogStream stream = docker.execStart(execId)) {
stream.readFully();
