Use yarn as a package manager

[lshapton]

• Updated scripts in package.json to use yarn instead of npm
• Ran yarn to generate yarn.lock file

[minasmart]

This is good! The only thing I would do, just to verify the lock file. do:

rm -rf node_modules
mv yarn.lock yarn.lock.old
yarn install
diff yarn.lock yarn.lock.old

If there's no diff, you're good. If there is, just remove the old lock file, and swap it out for the new one. Sometimes artifacts hang around when you're transitioning from npm to yarn and this will save us 😄

[lshapton]

@minasmart one small diff, adding the new lock file.