Don't build wasmbuild with wasmbuild

[dsherret]

We can't build wasmbuild with wasmbuild because we get this error when upgrading the version of wasm-bindgen 😅

error: Uncaught (in promise) Error: 

it looks like the Rust project used to create this wasm file was linked against
version of wasm-bindgen that uses a different bindgen format than this binary:

  rust wasm file schema version: 0.2.83
     this binary schema version: 0.2.81 (387e821c8)

Currently the bindgen format is unstable enough that these two schema versions
must exactly match. You can accomplish this by either updating the wasm-bindgen
dependency or this binary.

[dsherret]

Solving this in #52, by adding a deno task build:bindgen-upgrade, which will build wasmbuild using the globally installed wasm-bindgen-cli instead of the wasm file. Instructions will be located at https://github.com/denoland/wasmbuild/blob/main/contributing.md