ci: adding workflow for pr conventions

[hamza-m-masood]

Which problem does the PR fix?

related: https://github.com/camunda/camunda-platform-helm/issues/1581

What's in this PR?

Enforcing PR conventions

Checklist

Please make sure to follow our Contributing Guide.

Before opening the PR:

• [ ] In the repo's root dir, run make go.update-golden-only.
• [ ] There is no other open pull request for the same update/change.
• [ ] Tests for charts are added (if needed).
• [ ] In-repo documentation are updated (if needed).

After opening the PR:

• [ ] Did you sign our CLA (Contributor License Agreement)? It will show once you open the PR.
• [ ] Did all checks/tests pass in the PR?

[hamza-m-masood]

Interestingly when I only ahve one commit I get this error:

Error: Pull request has only one commit and it's not semantic; this may lead to a non-semantic commit in the base branch (see https://github.com/community/community/discussions/16271). Amend the commit message to match the pull request title, or add another commit.