Use of ed25519-dalek in wasm requires "wasm-bindgen" feature of getrandom crate

[vdods]

There is a runtime failure in getrandom in wasm target when using ed25519-dalek feature, which is fixed by adding

getrandom = { version = "0.1", features = ["wasm-bindgen"] }

to Cargo.toml. The problem is that this is only needed when the "ed25519-dalek" feature is used, and only for target_arch = "wasm32". I'm not quite sure how to specify this specific condition within Cargo.toml. Fortunately, adding the above line to my Cargo.toml does the trick, but ideally this could be specified within the ssi crate Cargo.toml.