add: Isotonic Regression

[adi271001]

Describe the algorithm/code

Isotonic regression is a regression technique in which the predictor variable is monotonically related to the target variable. This means that as the value of the predictor variable increases, the value of the target variable either increases or decreases in a consistent, non-oscillating manner. PLease assign me this issue under hacktoberfest tag

Do you want to work on this feature?

• I am willing to implement this feature.

[himanshu-03]

Hi @adi271001! 👋🏻
You can start working on this issue! Do let me know if you need any help. ✨

[adi271001]

created pull request and added codes