Documentation: Installation from source

[rootwork]

Describe the bug

I'm trying to get the latest version of the theme but it hasn't been updated on the Add-Ons site yet, so I want to install it from the file. The instructions for doing so don't match the current files in the repo, and I can't figure out what I need to do instead.

To Reproduce (if applicable) Steps to reproduce the behavior:

1. Read Installation > Manual (from source)
2. First instruction says "The first step is to download the theme, unzip the contents and re-create a zip only with the content of "monterail-dark" folder." However, there is no such folder. And none of the following options work:

• Creating a zipfile of the entire repo (monterail-dark-master)
• Creating a zipfile of the entire repo after removing the .github folder
• Creating a zipfile of just the content folder in the repo

In all three cases, after renaming the zipfile to .xpi and attempting to install, Thunderbird refuses and says the file is corrupt.

Which part(s) do we need to include when we're creating the zip? (Please update readme in addition to answering here.)

Thanks for this fantastic theme and your continuing work on it!

Build information (please complete the following information):

• OS: Linux Mint/Ubuntu 20.1
• Version: Thunderbird 78.7.1

Additional context

The reason I'm trying to install from source is there's no new release on Add-Ons and I want the fix to #65, so when you get a chance can you cut a new release?

[conema]

Hi @rootwork, The correct way is the first one, but you need to zip the content of the monterail-dark-master folder and not of the folder itself

[rootwork]

Thanks, that works!