Pinned fastapi version

[dcerisano]

Breaking changes in fastapi 0.100.0 broke EasyLM gradio webapp.
App server could not validate JSON, returned error code 422 on POST from client (see error below).

As per fastapi guidance, version should be pinned to prevent this in the future. Pinning back to previous version fastapi 0.99.1 resolves the issue for now, next version release should fix it. (Possible that other packages for EasyLM should be baselined as well).

Tested with:

• Today's clone of EasyLM repo
• open_llama_3b_easylm
• TR4 64GB DRAM + 12GB VRAM with XLA_PYTHON_CLIENT_ALLOCATOR=platform
• Ubuntu 22.04.2 LTS

INFO:     Started server process [51594]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
INFO:     Uvicorn running on http://0.0.0.0:5007 (Press CTRL+C to quit)
INFO:     127.0.0.1:33142 - "GET / HTTP/1.1" 200 OK
INFO:     127.0.0.1:33142 - "GET /info HTTP/1.1" 200 OK
INFO:     127.0.0.1:33142 - "GET /theme.css HTTP/1.1" 200 OK
INFO:     127.0.0.1:33142 - "POST /run/predict HTTP/1.1" 422 Unprocessable Entity
INFO:     ('127.0.0.1', 33152) - "WebSocket /queue/join" [accepted]
INFO:     connection open
INFO:     127.0.0.1:33162 - "POST /reset HTTP/1.1" 200 OK

[dcerisano]

Is this PR going to be merged? If it will be closed without merge a reason should be given. Assuming merge master is on vacation.