Create a WebhookMetadata from a comment added to an issue.

def build_from_issue_comment(gh_token, body):
    """Create a WebhookMetadata from a comment added to an issue.
    """
    if body["action"] in ["created", "edited"]:
        github_con = Github(gh_token)
        repo = github_con.get_repo(body['repository']['full_name'])
        issue = repo.get_issue(body['issue']['number'])
        text = body['comment']['body']
        try:
            comment = issue.get_comment(body['comment']['id'])
        except UnknownObjectException:
            # If the comment has already disapeared, skip the command
            return None
        return WebhookMetadata(repo, issue, text, comment)
    return None