Pin fastapi to > 0.90.1 to fix crash

See https://github.com/AUTOMATIC1111/stable-diffusion-webui/issues/11642#issuecomment-1643298659

This resolves a crashing bug for me on Python 3.10 and it appears to do so
as well for others.

requirements.txt

@@ -6,6 +6,7 @@ basicsr
 blendmodes
 clean-fid
 einops
+fastapi>=0.90.1
 gfpgan
 gradio==3.39.0
 inflection