Automatically convert shrinkwrap.yaml to pnpm-lock.yaml

[zkochan]

pnpm v3 uses a new lockfile format and it does not convert shrinkwrap.yaml to the new lockfile automatically.

For some pnpm users it may be important to be able to convert the lockfile to the new one.

related https://stackoverflow.com/questions/55284678/how-to-use-my-old-shrinkwrap-yaml-with-pnpm-3-0/55286082?noredirect=1#comment97338744_55286082