docs: add note about docker DNS config when using bridge mode (#12229) (

#12238)

The Docker DNS configuration options are not compatible with a
group-level network in `bridge` mode. Warn users about this in the
Docker task configuration docs.

website/content/docs/drivers/docker.mdx

@@ -98,13 +98,21 @@ config {
 }
 ```
 
-- `dns_search_domains` - (Optional) A list of DNS search domains for the container
-  to use.
-
-- `dns_options` - (Optional) A list of DNS options for the container to use.
-
-- `dns_servers` - (Optional) A list of DNS servers for the container to use
-  (e.g. ["8.8.8.8", "8.8.4.4"]). Requires Docker v1.10 or greater.
+- `dns_search_domains` - (Optional) A list of DNS search domains for
+  the container to use. If you are using bridge networking mode with a
+  `network` block in the task group, you must set all DNS options in
+  the `network.dns` block instead.
+
+- `dns_options` - (Optional) A list of DNS options for the container
+  to use. If you are using bridge networking mode with a `network`
+  block in the task group, you must set all DNS options in the
+  `network.dns` block instead.
+
+- `dns_servers` - (Optional) A list of DNS servers for the container
+  to use (e.g. ["8.8.8.8", "8.8.4.4"]). Requires Docker v1.10 or
+  greater. If you are using bridge networking mode with a `network`
+  block in the task group, you must set all DNS options in the
+  `network.dns` block instead.
 
 - `entrypoint` - (Optional) A string list overriding the image's entrypoint.