Run mypy in tox env and GH workflow

Author: abelcheung

.github/workflows/main.yml

@@ -30,6 +30,7 @@ jobs:
           - py310
           - py311
           - py312
+          - mypy
 
     # Use GitHub's Linux Docker host
     runs-on: ubuntu-latest

pyproject.toml

@@ -1,3 +1,6 @@
 [build-system]
 requires = ["setuptools>=61.0"]
 build-backend = "setuptools.build_meta"
+
+[tool.mypy]
+packages = ['lxml_html_clean']

tox.ini

@@ -1,9 +1,17 @@
 [tox]
-envlist = py36,py37,py38,py39,py310,py311,py312
+envlist = py36,py37,py38,py39,py310,py311,py312,mypy
 skipsdist = True
 
 [testenv]
 commands =
   python -m unittest tests.test_clean
   python -m doctest tests/test_clean_embed.txt tests/test_clean.txt tests/test_autolink.txt
 deps = lxml
+
+[testenv:mypy]
+commands =
+  mypy {posargs:}
+  mypy {posargs:} tests/test_clean.py
+deps =
+  mypy
+  types-lxml >= 2023.3.28