Add Renovate to Docker clients (#1267)

Renovate-bot looks at the container APIs directly to learn about new image versions and digests. The [default User-Agent](https://docs.renovatebot.com/self-hosted-configuration/#useragent) is `Renovate/${renovateVersion} (https://github.com/renovatebot/renovate)`

data/clients/docker-client.yaml

@@ -51,3 +51,10 @@
     all:
       - path.startsWith("/v2/")
       - userAgent.contains("containerd/")
+
+- name: allow-renovate
+  action: ALLOW
+  expression:
+    all:
+      - path.startsWith("/v2/")
+      - userAgent.contains("Renovate/")