Is your feature request related to a problem? Please describe.
Add an efficient implementation for the calculation of Fibonacci Numbers. Present implementations have O(N) time complexity. I would like to add an O(lgN) time complexity solution

Describe the solution you'd like
The approach would make use of matrix exponentiation to compute the nth Fib number

As part of Hacktoberfest 2021, I would like to enhance implementation of this class, could you please assign this to me @siriak.
Thank you