[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

include/openPMD/backend/Attributable.hpp

@@ -167,7 +167,7 @@ namespace internal
         [[nodiscard]] inline auto readAttribute(std::string const &name) const
             -> Attribute const &
         {
-            auto const & attr = attributes();
+            auto const &attr = attributes();
             if (auto it = attr.find(name); it != attr.end())
             {
                 return it->second;