Increase CED's max frame length to 3000 (#798)

so that it can process waves for up to 30 seconds.

@@ -24,7 +24,7 @@ base
 )
 
 for m in ${models[@]}; do
-  python3 ./export_onnx.py -m ced_$m
+  python3 ./export_onnx.py -m ced_$m --max-frames 3000
 done
 
 ls -lh *.onnx