Parallel builds fail on CI

[RareSecond]

🐛 Bug description

When using wasm-pack in a monorepo and running the build steps in parallel, the builds won't succeed. If you run them sequentially, they pass. There's probably a workaround to ensure the environment is in a good state (since the parallel build works locally), but I'm not sure what that would be.

🤔 Expected Behavior

Parallel builds should work on CI

👟 Steps to reproduce

Check the code and the checks in this reproducible example