It has been a long time since python3 was released, yet the monitoring plugin check_esxi_hardware was not compatible with python3. Until yesterday.
The initial reason for the delay (see issue #13) was the python module pywbem, which at first was only a module for python2. Since a new team took over the maintenance of pywbem, there was life yet again in pywbem and it was also ported to python3.
Second reason for the delay was: life. I already prepared a python3-compatible version a while ago, it just needed some more fine-tuning and testing. Finally this is now also completed and check_esxi_hardware now works on both python2 and python3. Same code, same plugin. That was very important to me to still be able to run the new version of the plugin on whatever environment.