message: add mkdir before copying
diff: #!/bin/sh
  set +e
  cargo +nightly build --target wasm32-unknown-unknown --release --verbose
  -cp target/wasm32-unknown-unknown/release/wallet_wasm.wasm ./js-example/html/wasm/cardano.wasm
  +mkdir -p js-example/html/wasm/ && cp target/wasm32-unknown-unknown/release/wallet_wasm.wasm ./js-example/html/wasm/cardano.wasm
  npm run build
  