pnpm: update to 8.12.0.

[Bnyro]

Testing the changes

• I tested the changes in this PR: YES

Local build testing

• I built this PR locally for my native architecture, x86_64-glibc

[kwshi]

By the way, the current pnpm package in void-packages (version 8.11.0) is broken-- the /usr/lib/node_modules/pnpm/package.json is empty, such that running pnpm results in the following error:

I'm not sure what was wrong with the 8.11 build script causing this to happen. However, I just tested this PR and that error no longer appears, so I think it fixes the issue-- in which case it would be best to merge this ASAP.

[Bnyro]

By the way, the current pnpm package in void-packages (version 8.11.0) is broken-- the /usr/lib/node_modules/pnpm/package.json is empty, such that running pnpm results in the following error:

I'm not sure what was wrong with the 8.11 build script causing this to happen. However, I just tested this PR and that error no longer appears, so I think it fixes the issue-- in which case it would be best to merge this ASAP.

Yes, that's my bad, not sure what went wrong when I tested 8.11.0 ... I likely tested the old version and forgot to actually install the new one back then.