🔧 chore(pyproject): add flake8 configuration

- set ignore rules for specific flake8 checks
- configure max line length to 88 characters

pyproject.toml

@@ -55,3 +55,7 @@ build-backend = "hatchling.build"
 
 [project.scripts]
 pdf2zh = "pdf2zh.pdf2zh:main"
+
+[tool.flake8]
+ignore = ["E203", "E261", "E501", "W503", "E741"]
+max-line-length = 88