Change readme back to use 0.4.x (#3188)

README.md

@@ -123,7 +123,7 @@ def index():
             rx.button("Generate Image", on_click=State.get_image, width="25em"),
             rx.cond(
                 State.processing,
-                rx.spinner(),
+                rx.chakra.circular_progress(is_indeterminate=True),
                 rx.cond(
                     State.complete,
                     rx.image(src=State.image_url, width="20em"),