cf_maintainer_bot

I've begun roughing out a script for helping folks do maintenance on their repos - automated version ticking, hash replacing, and rerendering. (It's definitely not a fully automated solution since it doesn't verify updated build requirements.) Its current home is at https://github.com/pmlandwehr/cf_maintainer_bot but I wouldn't mind moving it over to the main conda-forge organization if folks are interested in it.