Missed required_conversation_resolution field in branch protection rules

[g4s8]

GitHub added a new option for branch protection rules: Require conversation resolution before merging, v3 API also includes this new field as required_conversation_resolution (see example below). But current version (v36) of go-github doesn't include this field in protection struct.

Example API call:

{
  "url": "https://api.github.com/repos/g4s8/gitstrap/branches/master/protection", 
  "required_status_checks": {
    "url": "https://api.github.com/repos/g4s8/gitstrap/branches/master/protection/required_status_checks",
    "strict": true,
    "contexts": [
      "build",
      "lint",
      "test"
    ],
    "contexts_url": "https://api.github.com/repos/g4s8/gitstrap/branches/master/protection/required_status_checks/contexts"
  },
  "required_pull_request_reviews": {
    "url": "https://api.github.com/repos/g4s8/gitstrap/branches/master/protection/required_pull_request_reviews",
    "dismiss_stale_reviews": true,
    "require_code_owner_reviews": false,
    "required_approving_review_count": 1
  },
  "enforce_admins": {
    "url": "https://api.github.com/repos/g4s8/gitstrap/branches/master/protection/enforce_admins",
    "enabled": false
  },
  "required_linear_history": {
    "enabled": true
  },
  "allow_force_pushes": {
    "enabled": false
  },
  "allow_deletions": {
    "enabled": false
  },
  "required_conversation_resolution": {
    "enabled": false
  }
}