[site-reviews] add additional template tags

/**
 * @param array $tags
 * @param \GeminiLabs\SiteReviews\Review $review
 * @return array
 */
add_filter('site-reviews/review/build/after', function ($tags, $review) {
    $tags['rating_number'] = $review->rating;
    return $tags;
}, 10, 2);