Add env option SKIP_VERSION_CHECK forcing wasm-pack to use what's there

[asdil12]

This is especially useful within distro build environments

Make sure these boxes are checked! 📦✅

• You have the latest version of rustfmt installed

$ rustup component add rustfmt

• You ran cargo fmt on the code base before submitting
• You reference which issue is being closed in the PR text (there is no issue to reference)

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