fix relu example

Author: jalvesz

example/specialfunctions_activations/example_relu.f90

@@ -8,6 +8,6 @@ program example_relu
     implicit none
 
     x = linspace(-2._sp, 2._sp, n)
-    y = relu( x , 1.0 )
+    y = relu( x )
 end program example_relu