app.py: adjust txt2img steps defaults

app.py

@@ -225,7 +225,7 @@ with gr.Blocks(css=css) as demo:
                                 sampler = gr.Dropdown(value="DPM++ 2M Karras", show_label=True, label="Sampling Method", choices=prodia_client.list_samplers())
                                 
                             with gr.Column(scale=1):
-                                steps = gr.Slider(label="Sampling Steps", minimum=1, maximum=30, value=25, step=1)
+                                steps = gr.Slider(label="Sampling Steps", minimum=1, maximum=25, value=20, step=1)
     
                         with gr.Row():
                             with gr.Column(scale=1):