Add brew post-install troubleshooting tips

[dmarcotte]

There are a couple of important and common pitfalls users run into when install/upgrading Easy Move+Resize. For folks installing manually from this github repo, the install instruction have a troubleshooting section to help out.

brew users though, especially on upgrade, will not see this section which can cause problems and confusion. We can hopefully give them a bit of help too...

I imaging it's possible to configure some post-install notes like I've seen from many other brew packages to link to the troubleshooting section section so that even brew users have a chance to spot the tips as they need them.

[dmarcotte]

@metakirby5, @GianniTM, @victorpopkov, @suschizu — hey y'all. @mention'ing everyone here for two reasons:

1. most importantly, to say: THANK YOU! I only just realized that bumping the version for the cask install was a manual process, and I really appreciate all your help maintaining it. (Side note: is it an easy process? Can/should we add a note to the Release Process documentation to add this step?)

2. is this change described in this issue easy and would any of you be able to provide tips on how to accomplish this or even just go ahead and implement? (No pressure to do anything here—like I said, the important point is 1. above 🙏 )

[metakirby5]

Hello! To be honest, I forgot I had even added the cask in the first place 😅

1. IIRC it should be a pretty easy process, where we only need to change the version number and SHA based on the instructions, and submit a PR. I think it would be great to add more documentation, as you mentioned!
2. I think you can use the caveats stanza.

[dmarcotte]

Thank you, @metakirby5!