Modernization of the Gem

[Slavetomints]

This gem looks really neat, but it has some issues with not having been updated in the last 8 years on the gem branch. I'd love to do a PR, but I'd want to talk about what should be in it. Here's what I think should make it in, as well as some other suggestions:

• Update development dependencies versions
• Add Jekyll (4.0) as a runtime dependency
• Add 404.html page
• Add index.html page
• Migrate both branches to one main branch, and use GitHub Actions to deploy automatically upon push to main branch

Some other ideas I had were the following:

• Rename to jekyll-theme-researcher to better illustrate what this gem does upon first impression
• Rework SASS to have all be used in a single /assets/css/main.scss, and leave the files in _sass/ as just standalone files. There's no use in having it all collected included in _style.scss, and then including that in /assets/css/main.scss

I'd love to collaborate on what could be included in a modernization of the project!