Fixed Pumpkin website links

[LieOnLion]

Description

Changed the links in the README.md to link to the actual Pumpkin Website url (https://snowiiii.github.io/Pumpkin/ -> https://snowiiii.github.io/Pumpkin-Website/)

Testing

Click the links and they dont lead to a 404 page.

Checklist

Things need to be done before this Pull Request can be merged.

• Code is well-formatted and adheres to project style guidelines: cargo fmt
• Code does not produce any clippy warnings: cargo clippy
• All unit tests pass: cargo test
• I added new unit tests, so other people don't accidentally break my code by changing other parts of the codebase. How?

[Snowiiii]

Thanks @LieOnLion, I plan to get a domain soon