DEVEX-1087: fix common bump failing when already up to date

[pdodgen-revparts]

Summary

• Changes composer require to composer update in php-common-bump.yaml
• composer update exits 0 when the package is already at the latest version
• The commit step already handles the no-changes case (skips commit/push)
• Eliminates false-failure red marks in CI when there's nothing to update

Test plan

• Merge and verify next common bump on a repo that's already current shows green

[cursor]

PR Summary

Low Risk
Low risk workflow tweak: switches the bump step to composer update revolutionparts/common, reducing false CI failures without changing application/runtime code.

Overview
Prevents the PHP Common Bump GitHub Action from failing when revolutionparts/common is already at the latest version by changing the bump step from composer require to composer update.

This aligns with the existing “no changes to commit” logic so the workflow reports success when there’s nothing to update.

^{Reviewed by Cursor Bugbot for commit 00927e8. Bugbot is set up for automated code reviews on this repo. Configure here.}