COMP: Replace C++20 `auto` parameter w/ template (Normals)

include/otbNormalCompute.h

@@ -134,9 +134,9 @@ auto SimpleNormalMethodForRegularGrid(RealType x_spacing, RealType y_spacing)
  * The lamdba used will return the normalized value, or a triplet of `nodata`
  * if any of the two vertical or horizontal vector is null.
  */
-template <typename PointType>
+template <typename PointType, typename FloatType>
 inline
-auto SimpleNormalMethodForCartesianPoints(auto nodata)
+auto SimpleNormalMethodForCartesianPoints(FloatType nodata)
 {
   auto lambda = [=](
       Above<PointType> above, Left <PointType> left,