docs: document log-opts for "dual logging" cache
These options are available in Docker 20.10 and up, but were
previously only available in Docker EE, and not documented.
@@ -1400,6 +1400,10 @@ This is a full example of the allowed configuration options on Linux:
"log-driver": "json-file",
"log-level": "",
"log-opts": {
+ "cache-disabled": "false",
+ "cache-max-file": "5",
+ "cache-max-size": "20m",
+ "cache-compress": "true",
"env": "os,customer",
"labels": "somelabel",
"max-file": "5",
