Fix custom depth image

Currently the custom depth image is not working: it's not in the right format, and is supplied with an unknown argument (`depth`), and thus silently fails.
This was hard to catch, as the auto-generated depth map works so well.

app.py

@@ -36,8 +36,8 @@ def predict(input_image, prompt, negative_prompt, steps, num_samples, scale, see
         depth_image = pad_image(depth_image)
         depth_image = depth_image.resize((512, 512))
         depth = np.array(depth_image.convert("L"))
+        depth = np.expand_dims(depth, 0)
         depth = depth.astype(np.float32) / 255.0
-        depth = depth[None, None]
         depth = torch.from_numpy(depth)
     init_image = input_image.convert("RGB")
     image = pad_image(init_image)  # resize to integer multiple of 32
@@ -46,7 +46,7 @@ def predict(input_image, prompt, negative_prompt, steps, num_samples, scale, see
         image=image,
         prompt=prompt,
         negative_prompt=negative_prompt,
-        depth_image=depth,
+        depth_map=depth,
         seed=seed,
         strength=strength,
         num_inference_steps=steps,