Use manifest

Author: tsutsu3

MANIFEST.in

@@ -1,2 +1,4 @@
 include CHANGELOG.md
 include tox.ini
+include test/utils.py
+recursive-include test/fixtures *.txt

pyproject.toml

@@ -35,9 +35,6 @@ dev = ["pre-commit", "isort", "flake8", "black", "pyproject-flake8"]
 benchmark = ["pytest", "pytest-benchmark"]
 doc = ["sphinx", "sphinx_book_theme", "myst-parser"]
 
-[tool.setuptools]
-packages = ["linkify_it", "test"]
-
 [tool.setuptools.dynamic]
 version = {attr = "linkify_it.__version__"}