BUILD: Resort to namespace packaging for (pseudo-)data directories

Refer to:
  - [setuptools docs](https://setuptools.pypa.io/en/latest/userguide/datafiles.html\#subdirectory-for-data-files)
  - [PEP-420](https://peps.python.org/pep-0420/)
  - [pypa/setuptools#3340](pypa/setuptools#3340)

MANIFEST.in

@@ -21,7 +21,6 @@ exclude .mailmap
 exclude .pre-commit-config.yaml
 exclude .readthedocs.yaml
 exclude README.md
-exclude CONTRIBUTING.md
 exclude CITATION.md
 exclude CITATION.cff
 exclude NOTES.md

pyproject.toml

@@ -57,21 +57,16 @@ Documentation = "https://triumvirate.readthedocs.io/"
 Source = "https://github.com/MikeSWang/Triumvirate"
 Changelog = "https://github.com/MikeSWang/Triumvirate/blob/main/CHANGELOG.md"
 
-[tool.setuptools]
-include-package-data = true
+# [tool.setuptools]
+# include-package-data = true
 
 [tool.setuptools.dynamic]
 # version = {attr = 'triumvirate.__version__'}
 readme = {file = "README.rst"}
 
-[tool.setuptools.packages.find]
-where = ['src']
-namespaces = false
-exclude = [
-    'triumvirate.include*',
-    'triumvirate.src*',
-    'triumvirate.resources*',
-]
+# [tool.setuptools.packages.find]
+# where = ['src']
+# namespaces = true
 
 [tool.setuptools.package-data]
 'triumvirate' = ["*.pxd", "*.pyx"]

setup.cfg

@@ -30,7 +30,7 @@ project_urls =
     Changelog = https://github.com/MikeSWang/Triumvirate/blob/main/CHANGELOG.md
 
 [options]
-packages = find:
+packages = find_namespace:
 package_dir=
     =src
 include_package_data = True
@@ -57,10 +57,6 @@ nbk =
 
 [options.packages.find]
 where = src
-exclude =
-    triumvirate.include*
-    triumvirate.src*
-    triumvirate.resources*
 
 [options.package_data]
 triumvirate =
@@ -70,8 +66,6 @@ triumvirate.include =
     *.hpp
 triumvirate.src =
     *.cpp
-triumvirate.src.modules =
-    *.cpp
 triumvirate.resources =
     *.ini
     *.yml