yarn: updated to 1.19.2

1.19.2
Folders like .cache won't be pruned from the node_modules after each install.
Correctly installs workspace child dependencies when workspace child not symlinked to root.
Makes running scripts with Plug'n Play possible on node 13.
Change run command to check cwd/node_modules/.bin for commands. Fixes run in workspaces.

(adam)