Actions should do checking #11

Deno includes some analysis tools. Running deno run check will execute all three of them:

• deno fmt --check checks if everything is formatted according to deno fmt
• deno lint will run a linter
• deno check **/*.ts **/*.tsx will run typescript type checking

In my personal opinion, formatters/linters can be somewhat annoying, but most of my personal frustration comes from linters that have a bunch of arbitrary rules and no way to auto-fix them, I believe deno can just fix them for you so it's no big deal. Type checking should definitely be done though, that indicates a logic error