_determine_last_relevant_keyword: handle the new IFNOTEXISTS keyword so that columns in "CREATE TABLE IF NOT EXISTS foo" statements are properly detected

Author: macbre

sql_metadata/parser.py

@@ -1005,6 +1005,7 @@ def _determine_last_relevant_keyword(self, token: SQLToken, last_keyword: str):
                     and self._open_parentheses[-1].is_partition_clause_start
                 )
                 and not (token.normalized == "USING" and last_keyword == "SELECT")
+                and not (token.normalized == "IFNOTEXISTS")
             ):
                 last_keyword = token.normalized
         return last_keyword