Client support for Rekor V2: sigstore-python

Description

The new RekorV2 will support ed25519 keys. We should add support for this key type.

• https://github.com/sigstore/rekor-tiles/blob/c99e15d8a668fc34fc101548ae3e30092def0fd4/compose.yml#L63

• sigstore-python/sigstore/_internal/trust.py

  Lines 144 to 160 in 572ccac

  	if isinstance(self.key, rsa.RSAPublicKey):
  	self.key.verify(
  	signature=signature,
  	data=data,
  	# TODO: Parametrize this as well, for PSS.
  	padding=padding.PKCS1v15(),
  	algorithm=self.hash_algorithm,
  	)
  	elif isinstance(self.key, ec.EllipticCurvePublicKey):
  	self.key.verify(
  	signature=signature,
  	data=data,
  	signature_algorithm=ec.ECDSA(self.hash_algorithm),
  	)
  	else:
  	# Unreachable without API misuse.
  	raise VerificationError(f"keyring: unsupported key: {self.key}")