chore(sdk/python): bump to 0.5.4b1 for API parity beta

Test release covering the API-parity work in this PR:
- importlib.metadata-backed __version__
- cloud_vendor / cloud_product on InfoResponse
- not_before / not_after / with_app_info on get_tls_key (0.5.7+ gated)
- real ECDSA recovery in verify_env_encrypt_public_key, with timestamp
  v1 + legacy fallback (BREAKING: 4th positional arg required; the old
  no-op verify_signature_simple is removed)
- ethereum extras now resolve to eth-account instead of full web3

Author: Leechael

sdk/python/pyproject.toml

@@ -4,7 +4,7 @@
 
 [project]
 name = "dstack-sdk"
-version = "0.5.4b0"
+version = "0.5.4b1"
 description = "dstack SDK for Python"
 authors = [
     {name = "Leechael Yim", email = "yanleech@gmail.com"},