The plugin is now a part of OBS (Classic). Updated code can be found here:
https://github.com/jp9000/OBS/tree/master/scenesw
Originally it was created by ThoNohT and chris84
See: https://obsproject.com/forum/resources/simple-scene-switcher.29/ for more Info
I am not the author or creator of this Tool. ThoNoht and chris84 created it and
I just got the code from them. I host it here so it will never get lost.