Update flake8 requirement from <7.0.0,>=6.0.0 to >=6.0.0,<8.0.0

Updates the requirements on [flake8](https://github.com/pycqa/flake8) to permit the latest version.
- [Commits](PyCQA/flake8@6.0.0...7.0.0)

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

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

pyproject.toml

@@ -57,7 +57,7 @@ test = [
 ]
 check = [
     "mypy>=0.990",
-    "flake8>=6.0.0,<7.0.0",
+    "flake8>=6.0.0,<8.0.0",
     "flake8-black",
     "flake8-colors",
     "flake8-isort>=6.0.0,<7.0.0",