Upgrade xformers

modules/launch_utils.py

@@ -223,7 +223,7 @@ def prepare_environment():
     torch_command = os.environ.get('TORCH_COMMAND', f"pip install torch==2.0.1 torchvision==0.15.2 --extra-index-url {torch_index_url}")
     requirements_file = os.environ.get('REQS_FILE', "requirements_versions.txt")
 
-    xformers_package = os.environ.get('XFORMERS_PACKAGE', 'xformers==0.0.17')
+    xformers_package = os.environ.get('XFORMERS_PACKAGE', 'xformers==0.0.20')
     gfpgan_package = os.environ.get('GFPGAN_PACKAGE', "https://github.com/TencentARC/GFPGAN/archive/8d2447a2d918f8eba5a4a01463fd48e45126a379.zip")
     clip_package = os.environ.get('CLIP_PACKAGE', "https://github.com/openai/CLIP/archive/d50d76daa670286dd6cacf3bcd80b5e4823fc8e1.zip")
     openclip_package = os.environ.get('OPENCLIP_PACKAGE', "https://github.com/mlfoundations/open_clip/archive/bb6e834e9c70d9c27d0dc3ecedeebeaeb1ffad6b.zip")

webui.py

@@ -135,7 +135,7 @@ there are reports of issues with training tab on the latest version.
 Use --skip-version-check commandline argument to disable this check.
         """.strip())
 
-    expected_xformers_version = "0.0.17"
+    expected_xformers_version = "0.0.20"
     if shared.xformers_available:
         import xformers