Palindromic Pattern in CPP

[Anushka310]

I would like to contribute to this repo by adding code for the Palindromic pattern in C++.
The pattern for n = 4 is as follows:
_1
_2 1 2
3 2 1 2 3
4 3 2 1 2 3 4

Please @hhhrrrttt222111 assign me this under hacktoberfest label.

[Nishant Shaklan]

just add it