feat: add support for image generation using gpt-image-1 (#971)

* feat: add gpt-image-1 support

* feat: add example to generate image using gpt-image-1 model

* style: missing period in comments

* feat: add missing fields to example

* docs: add GPT Image 1 to README

* revert: keep `examples/images/main.go` unchanged

* docs: remove unnecessary newline from example in README file

examples/images/main.go

@@ -25,4 +25,4 @@ func main() {
 		return
 	}
 	fmt.Println(respUrl.Data[0].URL)
-}
+}