message: Python: `text` parameter must be optional for build_taa
diff: @@ -1497,7 +1497,7 @@ async def build_get_auth_rule_request(submitter_did: Optional[str],
  async def build_txn_author_agreement_request(submitter_did: str,
  - text: str,
  + text: Optional[str],
  version: str,
  ratification_ts: Optional[int] = None,
  retirement_ts: Optional[int] = None) -> str:
  @@ -1547,7 +1547,7 @@ async def build_txn_author_agreement_request(submitter_did: str,
  build_txn_author_agreement_request.cb = create_cb(CFUNCTYPE(None, c_int32, c_int32, c_char_p))
  c_submitter_did = c_char_p(submitter_did.encode('utf-8'))
  - c_text = c_char_p(text.encode('utf-8'))
  + c_text = c_char_p(text.encode('utf-8')) if text is not None else None
  c_version = c_char_p(version.encode('utf-8'))
  c_ratification_ts = c_int64(ratification_ts) if ratification_ts is not None else c_int(-1)
  c_retirement_ts = c_int64(retirement_ts) if retirement_ts is not None else c_int(-1)
  