Health Decrease Function

[DevJessParker]

User Story:

• A user's pet will have its stats naturally decrease over time, prompting the need to interact with their pet.

Steps to complete:

• [ ] Create a function to handle the decrease of stats over time.
• [ ] Rely on the setInterval or setTimeout functions as appropriate.
• [ ] If a pet's stat falls below zero, call a function that will end the game.