Fix the method

Author: thiagoromanos

aries_cloudagent/ledger/besu_vdr.py

@@ -152,7 +152,7 @@ async def fetch_schema_by_seq_no(self, seq_no: int) -> dict:
         LOGGER.error("SeqNo not available on Besu VDR")
         raise NotImplementedError
 
-    def credential_definition_id2schema_id(self, cred_def_id: str) -> str:
+    async def credential_definition_id2schema_id(self, cred_def_id: str) -> str:
         """Get schema id. Just regex, no need to search the ledger for this."""
 
         schema_id = cred_def_id.split("CLAIM_DEF/")[1].split("/")