#1 feat: update order utils to v2

Summary by cubic

Upgrade py_order_utils to Order V2 with EIP‑712 domain version "2" and a new order schema. Updates signatures/hashes and CI (Ubuntu 24.04 with actions/checkout@v6 and actions/setup-python@v6).

• New Features

  • EIP‑712 domain version "2".
  • V2 fields: millisecond timestamp (auto-filled), metadata/builder as bytes32 defaulting to ZERO_BYTES32. Removed taker, nonce, feeRateBps; expiration moved to SignedOrder.expiration.
  • Updated abi/Exchange.json, test addresses, and expected struct hashes/signatures.
  • Version bumps: package 0.3.6, kuest-py-eip712-structs 0.0.4.

• Migration

  • Do not pass taker, nonce, feeRateBps, or expiration in OrderData. Set timestamp (ms) or let the builder auto-fill; metadata and builder are optional.
  • Read expiration from SignedOrder.expiration. Verify EIP‑712 with domain version "2" and the new struct; expect new hashes/signatures.