feat: add cpp solution to lc porblem: No.0026 (#699)

Author: Bernhard-L

solution/0000-0099/0026.Remove Duplicates from Sorted Array/README_EN.md

@@ -100,6 +100,16 @@ public:
 };
 ```
 
+```cpp
+class Solution {
+public:
+    int removeDuplicates(vector<int>& nums) {
+        nums.erase(unique(nums.begin(), nums.end()), nums.end());
+        return nums.size();
+    }
+};
+```
+
 ### **Go**
 
 ```go