update scheduler setting

As posted [here](https://www.reddit.com/r/AnimeResearch/comments/x648bp/comment/in6vkpm/?utm_source=share&utm_medium=web2x&context=3), the default scheduler does not make good pictures.

README.md

@@ -56,7 +56,18 @@ model_id = "hakurei/waifu-diffusion"
 device = "cuda"
 
 
-pipe = StableDiffusionPipeline.from_pretrained(model_id, torch_dtype=torch.float16, revision='fp16')
+pipe = StableDiffusionPipeline.from_pretrained(
+    model_id,
+    torch_dtype=torch.float16,
+    revision="fp16",
+    scheduler=DDIMScheduler(
+        beta_start=0.00085,
+        beta_end=0.012,
+        beta_schedule="scaled_linear",
+        clip_sample=False,
+        set_alpha_to_one=False,
+    ),
+)
 pipe = pipe.to(device)
 
 prompt = "touhou hakurei_reimu 1girl solo portrait"