New Issue: Checking credentials

Checking credentials 🔐
Input: 1 email, 2 password.

Email must be in appropriate format.

Password must have a mixture of both uppercase and lowercase letters, a mixture of letters and numbers, 1 special character, and 1 number.

1. Write functions to check if email and password requirements are satisfied.

2. Write unit test for different combinations and make sure that it works as expected.

Link to the issue Checking credentials