build(deps): update pytest-flake8 requirement in /.dagger-ci/daggerci

Updates the requirements on [pytest-flake8](https://github.com/coherent-oss/pytest-flake8) to permit the latest version.
- [Release notes](https://github.com/coherent-oss/pytest-flake8/releases)
- [Changelog](https://github.com/coherent-oss/pytest-flake8/blob/main/NEWS.rst)
- [Commits](coherent-oss/pytest-flake8@v1.2.0...v1.3.0)

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

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

.dagger-ci/daggerci/requirements.txt

@@ -4,7 +4,7 @@ prettytable~=3.12
 pytest~=8.3
 pytest-benchmark~=5.1
 pytest-cov~=6.0
-pytest-flake8~=1.2
+pytest-flake8~=1.3
 pytest-pylint~=0.21
 pytest-timeout~=2.3
 PyYAML~=6.0