docs: replace sphinx-rtd-theme with sphinx-book-theme (#270)

Compared to `sphinx-rtd-theme`, `sphinx-book-theme` is a clean and
modern Sphinx theme.

Generated by the task: njzjz-bot/njzjz-bot#11.

docs/conf.py

@@ -32,7 +32,7 @@
     "deepmodeling_sphinx",
     "dargs.sphinx",
     "myst_parser",
-    "sphinx_rtd_theme",
+    "sphinx_book_theme",
     "sphinx.ext.viewcode",
     "sphinx.ext.intersphinx",
     "numpydoc",
@@ -54,7 +54,7 @@
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-html_theme = "sphinx_rtd_theme"
+html_theme = "sphinx_book_theme"
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,

pyproject.toml

@@ -45,10 +45,10 @@ dpgen2 = "dpgen2.entrypoint.main:main"
 docs = [
      'sphinx',
      'recommonmark',
-     'sphinx_rtd_theme>=1.0.0rc1',
+     'sphinx-book-theme',
      'numpydoc',
      'myst_parser',
-     'deepmodeling_sphinx',
+     'deepmodeling-sphinx>=0.3.0',
      'sphinx-argparse<0.5.0',
      "dargs>=0.4.1",
 ]