Update CI files to account for the master -> main rename (GH-25860)

.github/CONTRIBUTING.rst

@@ -4,7 +4,7 @@ Contributing to Python
 Build Status
 ------------
 
-- master
+- main
 
   + `Stable buildbots <http://buildbot.python.org/3.x.stable/>`_
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -16,7 +16,7 @@ Most PRs will require an issue number. Trivial changes, like fixing a typo, do n
 
 # Backport Pull Request title
 
-If this is a backport PR (PR made against branches other than `master`),
+If this is a backport PR (PR made against branches other than `main`),
 please ensure that the PR title is in the following format:
 
 ```
@@ -25,6 +25,6 @@ please ensure that the PR title is in the following format:
 
 Where: [X.Y] is the branch name, e.g. [3.6].
 
-GH-NNNN refers to the PR number from `master`.
+GH-NNNN refers to the PR number from `main`.
 
 -->

.github/workflows/build.yml

@@ -6,13 +6,13 @@ name: Tests
 on:
   push:
     branches:
-    - master
+    - main
     - 3.9
     - 3.8
     - 3.7
   pull_request:
     branches:
-    - master
+    - main
     - 3.9
     - 3.8
     - 3.7

.github/workflows/build_msi.yml

@@ -3,7 +3,7 @@ name: TestsMSI
 on:
   push:
     branches:
-    - master
+    - main
     - 3.9
     - 3.8
     - 3.7
@@ -11,7 +11,7 @@ on:
     - 'Tools/msi/**'
   pull_request:
     branches:
-    - master
+    - main
     - 3.9
     - 3.8
     - 3.7

.github/workflows/doc.yml

@@ -3,7 +3,7 @@ name: Docs
 on:
   #push:
   #  branches:
-  #  - master
+  #  - main
   #  - 3.9
   #  - 3.8
   #  - 3.7
@@ -11,7 +11,7 @@ on:
   #  - 'Doc/**'
   pull_request:
     branches:
-    - master
+    - main
     - 3.9
     - 3.8
     - 3.7