Fix docs build with sphinx-rtd-theme 3.0.0. (#209)

docs/conf.py

@@ -99,13 +99,6 @@ def get_version_and_release():
 #
 html_theme = "sphinx_rtd_theme"
 
-# Add any paths that contain custom themes here, relative to this directory.
-# Add path to the RTD explicitly to robustify builds (otherwise might
-# fail in a clean Debian build env)
-import sphinx_rtd_theme  # noqa: E402
-
-html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
-
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.