.asf.yaml: enforce pull request reviews and branch protection on master

[Swatantra-66]

Resolves #130

Summary & Context

In #130, @raiden00pl noted that direct git push to master succeeded without requiring a Pull Request or code review. @hartmannathan confirmed with Apache Infra that branch protection rules can be configured directly by the project via .asf.yaml (ASF Infra documentation).

Root Cause

In nuttx-website/.asf.yaml, the Default Branch Protection ruleset previously only enforced:

restrict_deletion: true
restrict_force_push: true

Because no pull request rule was declared, GitHub treated direct pushes to master as permissible for committers with write access.

Solution

This PR updates the Default Branch Protection ruleset in .asf.yaml using ASF Infra's convenience syntax to add pull request review and conversation resolution enforcement:

      required_conversation_resolution: true
      required_pull_request_reviews:
        dismiss_stale_reviews: true
        require_last_push_approval: true
        required_approving_review_count: 1

Key Behaviors & Guarantees

1. Blocks Accidental Direct Pushes: GitHub will immediately reject any direct git push to master or release/* branches with GH013: Repository rule violations found. All changes must be submitted via a Pull Request.
2. Review Requirement: Enforces at least 1 approving review from maintainers before merging (can easily be adjusted to 2 if the PMC prefers matching the core RTOS policy).
3. Conversation Resolution: Requires all review comment threads to be marked resolved before a PR can be merged.
4. Stale Review Dismissal: Automatically resets approvals when new commits are pushed, ensuring the final code state is reviewed.
5. No Disruption to Publishing: publish.sh deploys to the asf-site branch, which is untouched by this ruleset.
6. ASF Infra Compatibility: Preserves bypass_teams: [root], ensuring ASF Infrastructure administrative bots retain their required bypass access.

Verification

• Validated YAML schema syntax against apache/infrastructure-asfyaml parser specifications (valid_rulesets_convenience test matrix).
• Verified ruleset target applies strictly to ~DEFAULT_BRANCH (master) and release branches.

Signed-off-by: Swatantra Yadav maverickswatantra@gmail.com