Migrate from master to main

Author: HonkingGoose

.github/ISSUE_TEMPLATE/config.yml

@@ -1,7 +1,7 @@
 blank_issues_enabled: false
 contact_links:
   - name: Translation bug
-    url: https://github.com/progit/progit2/blob/master/TRANSLATING.md
+    url: https://github.com/progit/progit2/blob/main/TRANSLATING.md
     about: Refer to this table to find out where to report translation bugs.
 
   - name: Report bugs for git-scm.com site

.github/pull_request_template.md

@@ -3,7 +3,7 @@
 <!-- Should your changes appear in a printed edition, you'll be included in the contributors list. -->
 
 <!-- Mark the checkbox [X] or [x] if you agree with the item. -->
-- [ ] I provide my work under the [project license](https://github.com/progit/progit2/blob/master/LICENSE.asc).
+- [ ] I provide my work under the [project license](https://github.com/progit/progit2/blob/main/LICENSE.asc).
 - [ ] I grant such license of my work as is required for the purposes of future print editions to [Ben Straub](https://github.com/ben) and [Scott Chacon](https://github.com/schacon).
 
 ## Changes

.github/workflows/pr-build.yml

@@ -2,7 +2,7 @@ name: Pull Request Build
 
 on:
   pull_request:
-    branches: [ master ]
+    branches: [ main ]
 
 jobs:
   build:

.github/workflows/release-on-merge.yml

@@ -1,8 +1,8 @@
-name: Release on push to master
+name: Release on push to main
 
 on:
   push:
-    branches: [ master ]
+    branches: [ main ]
 
 jobs:
   release:
@@ -34,5 +34,5 @@ jobs:
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
         tag: ${{ steps.compute-tag.outputs.tagname }}
-        commit: master
+        commit: main
         artifacts: './progit.epub,./progit.mobi,./progit.pdf,./progit.html'

TRANSLATING.md

@@ -76,7 +76,7 @@ On https://git-scm.com, the translations are divided into three categories. Once
 
 GitHub Actions is a [continuous integration](https://en.wikipedia.org/wiki/Continuous_integration) service that integrates with GitHub. GitHub Actions is used to ensure that a pull-request doesn't break the build or compilation. GitHub Actions can also provide compiled versions of the book.
 
-The configuration for GitHub Actions is contained in the `.github/workflows` directory, and if you bring in the `master` branch of the root repository you'll get them for free.
+The configuration for GitHub Actions is contained in the `.github/workflows` directory, and if you bring in the `main` branch of the root repository you'll get them for free.
 However, if you created your translation repo by _forking_ the root repo, there's an extra step you must complete (if you did not fork, you can skip this part).
 GitHub assumes that forks will be used to contribute to the repo from which they were forked, so you'll have to visit the "Actions" tab on your forked repo, and click the "I understand my workflows" button to allow the actions to run.
 

atlas.json

@@ -1,5 +1,5 @@
 {
-  "branch": "master",
+  "branch": "main",
   "files": [
     "book/cover.html",
     "LICENSE.asc",