Use latest version of `mpesa` crate

[c12i]

Hi @dennohpeter. The current version of mpesa you are using, 0.4.2, is very outdated.

I recommend using a git version as I am preparing to release v1-beta very soon to crates.io:

[dependencies]
mpesa = { git = "https://github.com/collinsmuriuki/mpesa-rust" }

You can also install based on features you are using by choosing from the list below: b2b b2c account_balance c2b_register c2b_simulate express_request transaction_reversal

[dependencies]
mpesa = { git = "https://github.com/collinsmuriuki/mpesa-rust", default_features = false, features = ["b2b", "express_request"] }

[dennohpeter]

noted will do that bro