fix: allow int for colo(u)r for Guild.create_role

[AstreaTSS]

Pull Request Type

• Feature addition
• Bugfix
• Documentation update
• Code refactor
• Tests improvement
• CI/CD pipeline enhancement
• Other: [Replace with a description]

Description

A quick little fix for Guild.create_role to properly parse in ints for colo(u)r.

Changes

• Use an isinstance check to properly pass in value of color for the payload's color for Guild.create_role.

Related Issues

Fixes #1464.

Test Scenarios

Python Compatibility

• I've ensured my code works on Python 3.10.x
• I've ensured my code works on Python 3.11.x

Checklist

• I've run the pre-commit code linter over all edited files
• I've tested my changes on supported Python versions
• I've added tests for my code, if applicable
• I've updated / added documentation, where applicable