diff --git a/requirements.txt b/requirements.txt
deleted file mode 100644
index 8964dab..0000000
--- a/requirements.txt
+++ /dev/null
@@ -1 +0,0 @@
-flake8>=5.0.0,<6.0.0
diff --git a/setup.cfg b/setup.cfg
index e1de4f6..ae3d480 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -3,6 +3,3 @@ project_urls =
     Source=https://github.com/PyCQA/pep8-naming
     Issues=https://github.com/PyCQA/pep8-naming/issues
     Changelog=https://github.com/PyCQA/pep8-naming/blob/main/CHANGELOG.rst
-
-[options]
-install_requires = file: requirements.txt
diff --git a/setup.py b/setup.py
index af23f86..9884f4b 100644
--- a/setup.py
+++ b/setup.py
@@ -42,6 +42,7 @@ def run_tests(self):
     license='Expat license',
     package_dir={'': 'src'},
     py_modules=['pep8ext_naming'],
+    install_requires=['flake8>=5.0.0'],
     zip_safe=False,
     python_requires='>=3.7',
     entry_points={