this allows jsonfile logger to collect extra metadata from containers with
`--log-opt labels=label1,label2 --log-opt env=env1,env2`.
Extra attributes are saved into `attrs` attributes for each log data.
Signed-off-by: Daniel Dao <dqminh@cloudflare.com>
Upstream-commit: 0083f6e984894b4d3697c1ae63547c07eea697af
Component: engine