⬆️ bump cffi from 1.15.1 to 1.16.0

Bumps [cffi](https://github.com/python-cffi/cffi) from 1.15.1 to 1.16.0.
- [Release notes](https://github.com/python-cffi/cffi/releases)
- [Commits](python-cffi/cffi@v1.15.1...v1.16.0)

---
updated-dependencies:
- dependency-name: cffi
  dependency-type: indirect
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -21,7 +21,7 @@ certifi==2023.7.22
     #   httpcore
     #   httpx
     #   requests
-cffi==1.15.1
+cffi==1.16.0
     # via
     #   cmarkgfm
     #   cryptography