serde_json uses floats that may be disallowed in WASM

[tzemanovic]

Bug Summary

In https://github.com/anoma/namada we're compiling an IBC transaction code to WASM and found that the usage of serde_json includes a number parses that uses floats even when floats are not being used (e.g. from fn send_transfer_execute from crates/ibc/src/applications/transfer/relay/send_transfer.rs). This is problematic for deterministic WASM execution in which floats are disabled. From this serde-rs/json#567 there's a fork that feature-gates floats at https://github.com/nearprotocol/json that can be used in place

[Farhad-Shabani]

Thanks @tzemanovic for opening this issue.
There is a PR that should take care of this problem too. We place a higher priority on getting it done.

[tzemanovic]

that's great, thanks @Farhad-Shabani ! Using https://github.com/CosmWasm/serde-json-wasm looks like a good idea, I tried to use https://github.com/nearprotocol/json but I could still see some floats left in wasm