HMAC Cipher python implementation

[itspyguru]

1> Implement a HMAC Cipher encryption and decryption method and wrap it inside a class HMACCipher
2> save it to hmac_cipher.py
3> put the file inside decrypto/src folder
4> submit a PR.

Sample implementation : https://github.com/pyGuru123/Decrypto/blob/main/decrypto/src/binary_cipher.py
strictly follow above implementation and PEP8 Guidelines

[dollygupta07]

Hi @pyGuru123, I would like to work on this issue. Can you assign this to me?

[itspyguru]

sure, go for it. But strictly follow the methods provided with the issue