Document ACTIVATE_VERSION messages #71
Description
A number of taps and targets support ACTIVATE_VERSION messages, but I haven't been able to find any documentation in the spec clearly defining it. It's sometimes described in the source comments of some taps/targets or in the Singer slack channel, but these explanations aren't easy to find and aren't clearly defined.
Could we add a definition of ACTIVATE_VERSION somewhere in this repo? Happy to help where I can.