fix: update incompatible xformers version
diff --git a/launch.py b/launch.py
index 4269f1fcb..f545c39e6 100644
--- a/launch.py
+++ b/launch.py
@@ -42,7 +42,7 @@ def prepare_environment():
 
     if TRY_INSTALL_XFORMERS:
         if REINSTALL_ALL or not is_installed("xformers"):
-            xformers_package = os.environ.get('XFORMERS_PACKAGE', 'xformers==0.0.20')
+            xformers_package = os.environ.get('XFORMERS_PACKAGE', 'xformers==0.0.23')
             if platform.system() == "Windows":
                 if platform.python_version().startswith("3.10"):
                     run_pip(f"install -U -I --no-deps {xformers_package}", "xformers", live=True)

fixes https://github.com/lllyasviel/Fooocus/issues/2513

```
WARNING[XFORMERS]: xFormers can't load C++/CUDA extensions. xFormers was built for:
    PyTorch 2.0.1+cu118 with CUDA 1108 (you have 2.1.0+cu121)
    Python  3.10.11 (you have 3.10.9)
```

=> updating from 0.0.20 to 0.0.23