:green_heart: fix(pull_request): update link to contributing

[dylanmsql]

Pull request for Candy-doc

Your checklist for this pull request

🚨 Please review the guidelines for contributing to this repository.

• [X] Make sure you are requesting to pull a feature/bugfix branch (right side). Don't request your master!
• [X] Make sure you are making a pull request against the main branch (left side).
• [X] Check the commit's or even all commits' message styles matches our requested structure.
• [X] Check your code additions will fail neither code linting checks nor unit test.

Description

Update link to contributing.md in pull_request_template.md.

❤️ Thank you!