Simple docker container log grepping

Usage:
  dgrep CONTAINER [PATTERN] [flags]

Flags:
  -h, --help                     help for dgrep
  -i, --ignore-case              toggle to ignore case for the match (default true)
  -v, --invert-match             toggle to invert the match
      --ne stringArray           regular expression that must NOT be present
      --ne-exclude stringArray   exclude specific patterns from --std-errors (only works with --std-errors)
  -e, --regexp stringArray       regular expression to match (must be present)
  -r, --retry int                number of times to retry a failed request (default 3)
      --std-errors               check for 12 standard error patterns
  -t, --timeout duration         time to wait for logs to appear (default 15s)