Retain downstream tests and their source fixtures in sdists

Author: ketpatil77

pyproject.toml

@@ -192,8 +192,9 @@ exclude = [
     "doc-source",
 ]
 
-[tool.hatch.build.sdist]
-include = [ "domdf_python_tools", "requirements.txt",]
+[tool.hatch.build.targets.sdist]
+include = [ "domdf_python_tools", "requirements.txt", "tests", "tox.ini", ".github/milestones.py", "__pkginfo__.py", "doc-source/api/count_demo.py", "doc-source/conf.py", "doc-source/latex_unicode.py",]
+exclude = []
 
 [tool.hatch.build.wheel]
 include = [ "domdf_python_tools",]