add wasm support (#700)

* get started

* make it work again

* make it compile again

* Use async-wasm-feature of jsonrpsee from the master branch

* Ensure we enable JS feature of getrandom for the wasm target

* Update subxt/src/lib.rs

* update jsonrpsee

* fix CI

* cargo fmt

* fix wasm test

* fix grumbles

* exclude wasm-tests from workspace

To avoid leaking `jsonrpsee-web` feature into the workspace

Co-authored-by: Igor Matuszewski <xanewok@gmail.com>

codegen/src/utils/fetch_metadata.rs

@@ -71,7 +71,7 @@ async fn fetch_metadata_http(url: &Uri) -> Result<String, FetchMetadataError> {
         .request_timeout(Duration::from_secs(180))
         .build(url.to_string())?;
 
-    Ok(client.request::<String>("state_getMetadata", None).await?)
+    Ok(client.request("state_getMetadata", rpc_params![]).await?)
 }
 
 #[derive(Debug)]