Fixed clang c++20 compile

include/spdlog/logger.h

@@ -240,7 +240,7 @@ public:
         {
             // format to wmemory_buffer and convert to utf8
             fmt::wmemory_buffer wbuf;
-            fmt::format_to(std::back_inserter(wbuf), fmt, std::forward<Args>(args)...);
+            fmt::format_to(std::back_inserter(wbuf), fmt::runtime(fmt), std::forward<Args>(args)...);
 
             memory_buf_t buf;
             details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
@@ -340,7 +340,7 @@ protected:
         SPDLOG_TRY
         {
             memory_buf_t buf;
-            fmt::format_to(std::back_inserter(buf), fmt, std::forward<Args>(args)...);
+            fmt::format_to(std::back_inserter(buf), fmt::runtime(fmt), std::forward<Args>(args)...);
             details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
             log_it_(log_msg, log_enabled, traceback_enabled);
         }