go: add «26. Remove Duplicates from Sorted Array»

URL:	https://leetcode.com/problems/remove-duplicates-from-sorted-array/
Signed-off-by: Matej Focko <me@mfocko.xyz>

go/remove-duplicates-from-sorted-array.go

@@ -0,0 +1,14 @@
+package main
+
+func removeDuplicates(nums []int) int {
+	l := 1
+
+	for r := 1; r < len(nums); r++ {
+		if nums[r-1] != nums[r] {
+			nums[l] = nums[r]
+			l++
+		}
+	}
+
+	return l
+}