upgrade wasm-bindgen to 0.2.92 (paritytech#5056)

The rustc warns

```
The package `wasm-bindgen v0.2.87` currently triggers the following future incompatibility lints:
> warning: older versions of the `wasm-bindgen` crate will be incompatible with future versions of Rust; please update to `wasm-bindgen` v0.2.88
>   |
>   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
>   = note: for more information, see issue #71871 <rust-lang/rust#71871>
>
```