try to fix -Wchanges-meaning

Author: HuaHuaY

src/iceberg/table_metadata.h

@@ -87,7 +87,7 @@ struct ICEBERG_EXPORT TableMetadata {
   /// The highest assigned column ID for the table
   int32_t last_column_id;
   /// A list of schemas
-  std::vector<std::shared_ptr<Schema>> schemas;
+  std::vector<std::shared_ptr<iceberg::Schema>> schemas;
   /// ID of the table's current schema
   std::optional<int32_t> current_schema_id;
   /// A list of partition specs
@@ -122,7 +122,7 @@ struct ICEBERG_EXPORT TableMetadata {
   int64_t next_row_id;
 
   /// \brief Get the current schema, return NotFoundError if not found
-  Result<std::shared_ptr<Schema>> Schema() const;
+  Result<std::shared_ptr<iceberg::Schema>> Schema() const;
   /// \brief Get the current schema by ID, return NotFoundError if not found
   Result<std::shared_ptr<iceberg::Schema>> SchemaById(
       const std::optional<int32_t>& schema_id) const;