SelectionSort.cpp

Adding program of SelectionSort using CPP in [SelectionSort](https://github.com/BaReinhard/Hacktoberfest-Data-Structure-and-Algorithms/tree/master/algorithms/selection_sort)
@BaReinhard  .Please assign me this issue.

Selection sort is an algorithm that selects the smallest element from an unsorted list in each iteration and places that element at the beginning of the unsorted list.

