♻️ (sum, sum_test): modify array type to slice

Author: yuanyu90221

arrays-and-slices/sum.go

@@ -1,6 +1,6 @@
 package arrays_and_slices
 
-func Sum(numbers [5]int) int {
+func Sum(numbers []int) int {
 	sum := 0
 	for _, number := range numbers {
 		sum += number

arrays-and-slices/sum_test.go

@@ -4,7 +4,7 @@ import "testing"
 
 func TestSum(t *testing.T) {
 	t.Run("collection of 5 numbers", func(t *testing.T) {
-		numbers := [5]int{1, 2, 3, 4, 5}
+		numbers := []int{1, 2, 3, 4, 5}
 
 		got := Sum(numbers)
 		want := 15