Yarn is required for setup

[mtliendo]

The getting started section of the docs suggest that using npm is possible by running the command npx create-bison-app MyApp

However, upon doing so, I'm given an error about the yarn command failing.

[cball]

Great catch! we should definitely fix this.

[mtliendo]

Happy to help out on this one. The way I've seen it handled in other projects is by detecting the presence of a yarn.lock or package-lock.json file and then running the appropriate commands from there. Thoughts?