Updated app.py to use Aurora theme class

app.py

@@ -1,6 +1,6 @@
 import time
 import gradio as gr
-from aurora import aurora
+from aurora import Aurora
 import matplotlib.pyplot as plt
 import numpy as np
 import pandas as pd
@@ -263,4 +263,4 @@ with gr.Blocks() as demo:
                 gr.LinePlot(filtered_df, inputs=[ethnicity, max_age], x="age", y="height", title="Age x Height", label="Line Plot")
 
 if __name__ == "__main__":
-    demo.queue().launch(theme=aurora, css=aurora_css)
+    demo.queue().launch(theme=Aurora(), css=aurora_css)