🔧 Refactor: modernize outdated GitHub Actions workflow dependencies

[DiogoRibeiro7]

• Modules that will be modified:

  • .github/workflows/run_test_suite.yml
  • .github/workflows/deploy.yml

• Impact on code structure:

  • Update older GitHub Actions dependencies such as actions/checkout@v2, actions/setup-python@v2, and codecov/codecov-action@v3
  • Refresh the release workflow to use more modern publishing patterns
  • Keep the workflow scope the same; this is about modernizing implementation details rather than changing the CI matrix

• Impact on speed:

  • No expected runtime impact on the GPyTorch library itself
  • May improve CI/release maintainability and reduce workflow fragility

• Will this be a breaking change?

  • No expected breaking change to the Python package API
  • There may be small workflow or release-process changes that need validation after the update

[vivek41-glitch]

Hi! I'd like to work on this.
I'll update the GitHub Actions dependencies to their latest versions in both workflow files.