The examples fail to build on nightlies newer than `2020-05-24`

[rrbutani]

See rustwasm/wasm-bindgen#2158 for more details.

[rrbutani]

This is fixed in rustwasm/wasm-bindgen#2159; once that gets merged (and the PR in #1) we can switch back to wasm-bindgen proper and this issue can be closed.