Update Scoop installation in README.md

[r15ch13]

upm has been added to the main bucket with ScoopInstaller/Main@029935d

[raxod502]

This is wonderful. Sometime before the next release, we'll need to make sure the release system knows how to handle using the main Scoop bucket instead of a custom one.

[r15ch13]

Just push a new release to GitHub exactly like it is now (checksum.txt and semantic version) and it will be picked up by our update system automatically.

[raxod502]

@turbio Probably best to merge this PR given that there's now a duplicate: #21

[dan-stowell]

Good afternoon @r15ch13 ! You've probably noticed by now that we've been slow to merge community PRs on polygott. We've decided to focus on giving Repl.it a stable foundation instead of adding features and updating languages. Once we and our community feel comfortable with Repl.it's overall stability, we'll give this change another look. Thank you for contributing!

[raxod502]

This is only a documentation fix, I would suggest merging sooner rather than later.

[blast-hardcheese]

Thank you!