[Java] leetcode #70

[aayush26]

https://leetcode.com/problems/climbing-stairs/

[Alireza-Sampour]

@aayush26 I've sent PR for this

[ajanthasingam]

@aayush26 I've made a PR for this

[aayush26]

@ajanthasingam Java Binet's solution merged. Thanks for the contribution.

[jag-singh-96]

I have done the solution in java using Dp...Please review it