Use check-yarn-lock

[okonet]

Let's switch to yarn and use https://www.npmjs.com/package/check-yarn-lock with lint-staged to always commit lock file changes

[ryyppy]

I am not entirely convinced. I still believe that we should keep it simple and just continue with a pure npm workflow

[okonet]

What is so hard about yarn?

[nikgraf]

I also would prefer yarn. My question would be what's easier about npm?