chore(deps): update flake8 requirement in /bots/gsbot

Updates the requirements on [flake8](https://github.com/pycqa/flake8) to permit the latest version.
- [Commits](PyCQA/flake8@6.1.0...7.3.0)

---
updated-dependencies:
- dependency-name: flake8
  dependency-version: 7.3.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

bots/gsbot/requirements.txt

@@ -25,7 +25,7 @@ pytest-mock>=3.12.0
 
 # Code Quality
 black>=25.11.0
-flake8>=6.1.0
+flake8>=7.3.0
 mypy>=1.7.1
 pylint>=3.3.9