Bump tiktoken from 0.6.0 to 0.7.0

Bumps [tiktoken](https://github.com/openai/tiktoken) from 0.6.0 to 0.7.0.
- [Release notes](https://github.com/openai/tiktoken/releases)
- [Changelog](https://github.com/openai/tiktoken/blob/main/CHANGELOG.md)
- [Commits](openai/tiktoken@0.6.0...0.7.0)

---
updated-dependencies:
- dependency-name: tiktoken
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements.txt

@@ -3,6 +3,6 @@ flask<3.0.0
 requests==2.31.0
 simpleaichat==0.2.2
 openai<1.0.0
-tiktoken==0.6.0
+tiktoken==0.7.0
 google-cloud-storage==2.16.0
 google-auth==2.29.0