feat: Add Insertion sort

pkg/algo/sorting.go

@@ -0,0 +1,19 @@
+package algo
+
+import "fmt"
+
+func InsertionSort(a []int, n int) {
+	fmt.Println("-- Insertion Sort --")
+	fmt.Printf("Input: %v\n", a)
+
+	for i := 1; i < n; i++ {
+		key := a[i]
+		j := i - 1
+		for ; j >= 0 && a[j] > key; j-- {
+			a[j+1] = a[j]
+		}
+		a[j+1] = key
+	}
+
+	fmt.Printf("Output: %v\n", a)
+}