Remove parking_lot from direct dependency

[tetsuharuohzeki]

We don't use this crate now. This fix #882

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

✨✨ 😄 Thanks so much for contributing to wasm-pack! 😄 ✨✨

[ijackson]

Hi. FYI, my MR #924 reintroduces direct use of parking_lot, so this MR ought now to wait until we see what becomes of mine. Sorry to be making your cleanup obsolete...