fix xformers install

Dockerfile

@@ -55,7 +55,7 @@ RUN mkdir repositories && \
 
   pip install git+https://github.com/openai/CLIP.git@d50d76daa670286dd6cacf3bcd80b5e4823fc8e1 --prefer-binary && \
   # install xformers
-  pip install xformers --prefer-binary
+  pip install git+https://github.com/facebookresearch/xformers.git@v0.0.13#egg=xformers
 
 COPY --chown=sd ./requirements.txt ./requirements.txt
 RUN pip install -r requirements.txt  --prefer-binary