Update deprecated syntax in README.md

Author: musm

README.md

@@ -205,8 +205,8 @@ end
 write_matfile("test.mat"; 
 	a = Int32[1 2 3; 4 5 6], 
 	b = [1.2, 3.4, 5.6, 7.8], 
-	c = {[0., 1.], [1., 2.], [1., 2., 3.]}, 
-	d = {"name"=>"MATLAB", "score"=>100.}, 
+	c = [[0.0, 1.0], [1.0, 2.0], [1.0, 2.0, 3.0]], 
+	d = Dict("name"=>"MATLAB", "score"=>100.0), 
 	s = "abcde",
 	ss = [S(1.0, true, [1., 2.]), S(2.0, false, [3., 4.])] )
 ```