feat: Add Two Pair Sum Program

[khushis28]

The purpose of the program is to find pairs of elements in the arr vector that sum up to a specific target value (sum in this case), which is set to 80. The program iterates through the vector, comparing each element with all subsequent elements to check if their sum equals the target value. When such a pair is found, it is printed to the console.

[abhi-yo]

Can you please assign this to me