2021-10-20: initial release
2021-10-25: added update check
2021-10-26: minor fixes (removed unused prints)
2021-11-04: fixed missing "versions" key in "release" section
2021-11-17: added checkmk appliance version/downloads
2021-12-07: added metrics for patch release history (a little fun) maybe one day of (cache, only checks once a day)
2022-05-28: rewritten for new json format (THX at baris.leenders[at]tribe29 and martin.hirschvogel[at]tribe29 for supporting the development of this plugin)
            Note: before updateing remove the old agent_checkmk_download completely (rules and package)
2022-11-30: WATO: fixed CheckParameterRulespecWithoutItem (from CheckParameterRulespecWithItem)
2023-03-18: rewritten as a "normal" check plugin (no special agent)
            before updating to this version remove the special agent version (rules + package)
2023-03-19: added support for appliance firmware version
2023-03-28: added Checkmk Cloud Edition
2023-04-11: added support for beta/inovation branch, minor changes in the output
2023-05-19: changed metric data form stable/old stable to cmk/cfw main version
2023-07-06: moved to various
2023-07-06: changed position of items in detailed output
2023-07-07: added support for AlmaLinux and Rocky Linux
2023-07-08: added support for ol -> Oracle Linux
2023-07-10: added support for rhel -> Red Hat Enterprise Linux. THX to Rickard Eriksson
2024-01-01: fixed missing download CMK URL in service details
            moved WATO/metrics from ~/local/share/check_mk/web/.. to ~/var/lib/checkmk/gui/.. for CMK 2.2.0
            METRICS: prepared for CMK 2.3.0
2024-04-30: refactoring for CMK 2.3.0 (adjusted to new section_lnx_distro format only)