feat(ResultInfo): add TotalPages field

This changes adds the `TotalPages` field to the `ResultInfo` struct.

This field was added to the API a while ago and can be used in
combination with the `Pages` field to determine how many more calls you
need to make to fetch all data.

cloudflare.go

@@ -160,8 +160,9 @@ type Response struct {
 
 // ResultInfo contains metadata about the Response.
 type ResultInfo struct {
-	Page    int `json:"page"`
-	PerPage int `json:"per_page"`
-	Count   int `json:"count"`
-	Total   int `json:"total_count"`
+	Page       int `json:"page"`
+	PerPage    int `json:"per_page"`
+	TotalPages int `json:"total_pages"`
+	Count      int `json:"count"`
+	Total      int `json:"total_count"`
 }