Fix typo in app.py

Fixing a small typo in app.py ("Coluns" -> "Columns")

app.py

@@ -117,7 +117,7 @@ if __name__ == "__main__":
             batch_size.render()
 
             rows = gr.Number(2, label="Rows")
-            columns = gr.Number(5, label="Coluns")
+            columns = gr.Number(5, label="Columns")
 
             rows.change(update_shape, [rows, columns], [gallery])
             columns.change(update_shape, [rows, columns], [gallery])