v0.2.0

• Add --strict option that will suppress input lines that are not valid
  ecs-logging records. Normally non-ecs-logging records are passed through
  unchanged.

• Support there not being a "message" field (allowed in ecs-logging spec
  in elastic/ecs-logging#55).

• Fix a bug in the "simple" formatter, where the ellipsis would always be
  printed because the "@timestamp" field was not discounted.

• Refactor the read loop to handle very long lines without crashing, and without
  using unbounded memory. One side-effect -- due to the usage of
  bufio.Reader.ReadLine -- is that ecslog output will always finish with a
  newline, even if the input did not.

• Potentially much faster passing through unprocessed lines, moving to
  out.Write instead of unnecessary usage of fmt.Fprintln.