Replace git master with main or default branch in docs

Author: manics

RELEASE.md

@@ -62,10 +62,10 @@ Also the images we build are based on some image specified in the `FROM` stateme
 
   - [ ] Create and push a git tag
     ```bash
-    git checkout master
-    git reset --hard <upstream>/master
-    git tag -a x.y.z-beta.1 -m x.y.z-beta.1 <commit on master>
-    git push --follow-tags <upstream> master
+    git checkout main
+    git reset --hard <upstream>/main
+    git tag -a x.y.z-beta.1 -m x.y.z-beta.1 <commit on main>
+    git push --follow-tags <upstream> main
     ```
 
 - Announce the x.y.z-beta.1 release
@@ -86,10 +86,10 @@ Also the images we build are based on some image specified in the `FROM` stateme
   - [ ] Create and push a git tag.
 
     ```bash
-    git checkout master
-    git reset --hard <upstream>/master
+    git checkout main
+    git reset --hard <upstream>/main
     git tag -a x.y.z -m x.y.z HEAD
-    git push --follow-tags <upstream> master
+    git push --follow-tags <upstream> main
     ```
 
   - [ ] Create a GitHub release.

doc/source/conf.py

@@ -277,7 +277,7 @@ def parse_schema(d, md=[], depth=0, pre=""):
 html_context = {
     "github_user": "jupyterhub",
     "github_repo": "zero-to-jupyterhub-k8s",
-    "github_version": "master",
+    "github_version": "main",
     "doc_path": "doc/source",
 }
 

doc/source/repo2docker.md

@@ -108,7 +108,7 @@ to configure JupyterHub to build off of this image:
        <a-git-repository-url>
    ```
 
-   This tells `repo2docker` to fetch `master` of the Git repository, and
+   This tells `repo2docker` to fetch the default branch of the Git repository, and
    uses heuristics to build a Docker image of it.
 
 6. **Push the newly-built Docker image to your repository.**