Fixed docs/source/conf.py

Author: JohanMabille

docs/source/conf.py

@@ -16,7 +16,7 @@
 html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 def setup(app):
-    app.add_stylesheet("main_stylesheet.css")
+    app.add_css_file("main_stylesheet.css")
 
 extensions = ['breathe']
 breathe_projects = { 'xtensor-r': '../xml' }