Bump cryptography in /examples/reservations-bot-demo/cloud_function

Bumps [cryptography](https://github.com/pyca/cryptography) from 3.3.2 to 39.0.1.
- [Release notes](https://github.com/pyca/cryptography/releases)
- [Changelog](https://github.com/pyca/cryptography/blob/main/CHANGELOG.rst)
- [Commits](pyca/cryptography@3.3.2...39.0.1)

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

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

examples/reservations-bot-demo/cloud_function/requirements.txt

@@ -1,7 +1,7 @@
 certifi==2020.6.20
 cffi==1.14.2
 chardet==3.0.4
-cryptography==3.3.2
+cryptography==39.0.1
 enum-compat==0.0.3
 googleapis-common-protos==1.52.0
 grpcio==1.31.0