Fix warnings

include/fmt/safe-duration-cast.h

@@ -258,13 +258,15 @@ To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
   // multiply with Factor::num without overflow or underflow
   if (Factor::num != 1) {
     constexpr auto max1 =
-        std::numeric_limits<IntermediateRep>::max() / Factor::num;
+        std::numeric_limits<IntermediateRep>::max() /
+        static_cast<IntermediateRep>(Factor::num);
     if (count > max1) {
       ec = 1;
       return {};
     }
     constexpr auto min1 =
-        std::numeric_limits<IntermediateRep>::lowest() / Factor::num;
+        std::numeric_limits<IntermediateRep>::lowest() /
+        static_cast<IntermediateRep>(Factor::num);
     if (count < min1) {
       ec = 1;
       return {};