Added required permissions for Release Drafter workflow to function properly

[sakina1303]

This PR adds the required permissions for the Release Drafter workflow to function properly with Dependabot PRs.
with the help of the docs, I observed that the workflow needed:

• contents: write
• pull-requests: write

In order to ensure Release Drafter can properly draft releases for Dependabot PRs and be manually triggered if needed,
I also added (workflow_dispatch) to enable manual triggering of the workflow for testing purposes.

Testing done

• YAML syntax validated locally.
• Changes pushed to a separate branch: fix/release-drafter-permissions-clean.
• Manual workflow run not tested due to permission limitations on forked repositories

Submitter checklist

[x] Opened from a feature branch (fix/release-drafter-permissions-clean)
[x] PR title clearly reflects the changelog purpose
[x] Described the changes clearly
[x] Verified file structure and syntax
[x] Change is small and scoped properly

Fixes #84

[jglick]

#114 (comment) FWIW