Bump fastapi from 0.65.2 to 0.109.1 in /chap-four

Bumps [fastapi](https://github.com/tiangolo/fastapi) from 0.65.2 to 0.109.1.
- [Release notes](https://github.com/tiangolo/fastapi/releases)
- [Commits](fastapi/fastapi@0.65.2...0.109.1)

---
updated-dependencies:
- dependency-name: fastapi
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

chap-four/requirements.txt

@@ -1,5 +1,5 @@
 # minimal production requirements
-fastapi==0.65.2
+fastapi==0.109.1
 torch==1.9.0
 transformers==4.9.2
 uvicorn==0.14.0