Use integrity Field from yarn.lock as sha512 for Nix Derivation

[pathway27]

The newset yarn version (1.22.19) generates yarn.lock files which don't have the sha1 in their url with a #, so fails for some users. One public example I've found: https://github.com/iptv-org/iptv/blob/master/yarn.lock#L7.

But I notice most lockfiles have an integrity field. See https://github.com/canva-public/js2nix/blob/main/yarn.lock#L8

[CLAassistant]

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[olebedev]

Hey @pathway27, thanks for raising this issue, this is true, we can leverage this field from the modern-built lockfiles.

The build seems failing, would you mind to fix it before the review? Thanks!