MAINT: changes related to default branch renaming (#64)

* Update master->main for CI configuration.

* Update binder and sphinx theme.

* Update doc references to master.

Author: rossbar

.circleci/config.yml

@@ -76,4 +76,4 @@ workflows:
             - build-docs
           filters:
             branches:
-              only: master
+              only: main

content/tutorial-style-guide.md

@@ -85,7 +85,7 @@ Avoid abstraction. "About" is a tipoff: Rather than writing "You'll learn about
 
 ## Avoid asides
 
-As explained by master documentation writer [Daniele Procida](https://documentation.divio.com/tutorials):
+As explained by expert documentation writer [Daniele Procida](https://documentation.divio.com/tutorials):
 
 > Don’t explain anything the learner doesn’t need to know in order to complete the tutorial. 
 

site/conf.py

@@ -1,9 +1,5 @@
 # Configuration file for the Sphinx documentation builder.
 #
-# This file only contains a selection of the most common options. For a full
-# list see the documentation:
-# https://www.sphinx-doc.org/en/master/usage/configuration.html
-
 # -- Path setup --------------------------------------------------------------
 
 # If extensions (or modules to document with autodoc) are in another directory,
@@ -56,7 +52,7 @@
 html_theme_options = {
     "github_url": "https://github.com/numpy/numpy-tutorials/",
     "repository_url": "https://github.com/numpy/numpy-tutorials/",
-    "repository_branch": "master",
+    "repository_branch": "main",
     "use_repository_button": True,
     "use_issues_button": True,
     "use_edit_page_button": True,

site/index.md

@@ -2,7 +2,7 @@
 
 [![Binder](https://mybinder.org/badge_logo.svg)][launch_binder]
 
-[launch_binder]: https://mybinder.org/v2/gh/numpy/numpy-tutorials/master?urlpath=lab/tree/content
+[launch_binder]: https://mybinder.org/v2/gh/numpy/numpy-tutorials/main?urlpath=lab/tree/content
 
 This set of tutorials and educational materials is being developed,
 IT IS NOT INTEGRATED IN THE HTML DOCS AT <https://www.numpy.org/devdocs/>