ci: add push trigger to zizmor workflow for changes to workflow files on main#973

Copilot wants to merge 2 commits intomainCycloneDX/cyclonedx-python-lib:mainfrom

copilot/update-zizmor-workflow-triggerCycloneDX/cyclonedx-python-lib:copilot/update-zizmor-workflow-triggerCopy head branch name to clipboard