update module workflows (cloudeteer/terraform-governance#58)

[lixhunter]

Description

This pull request includes changes to the GitHub Actions workflows to streamline and improve the CI/CD process. The most important changes involve modifications to the triggers for workflows and the addition of a new workflow for managing GitHub modules.

Changes to workflow triggers:

• .github/workflows/module-ci.yaml: Removed the push trigger for the main branch and the labeled and unlabeled triggers for pull requests.

Addition of a new workflow:

• .github/workflows/module-manage-github.yaml: Added a new workflow named module-manage-github that triggers on push to the main branch, on issue creation, and on specific pull request events (opened, labeled, unlabeled).

PR Checklist

• I have checked if my changes close any open issues. If so please include appropriate closing keywords below.
• I have updated/added documentation written in a helpful and kind way to assist users that may be unfamiliar with the resource / data source.
• I have checked for a proper tag for this PR: breaking-change, feature, fix, other, ignore-release
• I have used a meaningful PR title to help maintainers and other users understand this change and help prevent duplicate work.

Motivation and Context

relates to cloudeteer/terraform-governance#58

Breaking Changes

None.