• Fixed the Docker health-check script to use the correct time of
  the last update attempt. Reported by cford1080. GitHub #225.
• Added new --output flag to print JSON to standard output describing
  the result of the run.
• Compilation with Go versions before 1.19 is no longer supported.
• When using the provided Docker images, geoipupdate no longer runs
  as root in the container. Based on pull request by Andreas
  Grünenfelder. GitHub #200.