docs: update references to renovate/renovate to v37.139.4

| datasource | package           | from     | to       |
| ---------- | ----------------- | -------- | -------- |
| docker     | renovate/renovate | 37.131.0 | 37.139.4 |

docs/usage/docker.md

@@ -383,7 +383,7 @@ To get access to the token a custom Renovate Docker image is needed that include
 The Dockerfile to create such an image can look like this:
 
 ```Dockerfile
-FROM renovate/renovate:37.131.0
+FROM renovate/renovate:37.139.4
 # Include the "Docker tip" which you can find here https://cloud.google.com/sdk/docs/install
 # under "Installation" for "Debian/Ubuntu"
 RUN ...