Revert "[automated] Change default branch to master"

This reverts commit 32a08fea5d.

.appveyor.yml

@@ -2,7 +2,7 @@ init:
 - git config --global core.autocrlf true
 branches:
   only:
-  - master
+  - dev
   - /^release\/.*$/
   - /^(.*\/)?ci-.*$/
 build_script:

.travis.yml

@@ -16,7 +16,7 @@ addons:
     - libunwind8
 branches:
   only:
-  - master
+  - dev
   - /^release\/.*$/
   - /^(.*\/)?ci-.*$/
 before_install:

run.ps1

@@ -52,8 +52,8 @@ in the file are overridden by command line parameters.
 Example config file:
 ```json
 {
-  "$schema": "https://raw.githubusercontent.com/aspnet/BuildTools/master/tools/korebuild.schema.json",
-  "channel": "master",
+  "$schema": "https://raw.githubusercontent.com/aspnet/BuildTools/dev/tools/korebuild.schema.json",
+  "channel": "dev",
   "toolsSource": "https://aspnetcore.blob.core.windows.net/buildtools"
 }
 ```
@@ -192,7 +192,7 @@ if (!$DotNetHome) {
         else { Join-Path $PSScriptRoot '.dotnet'}
 }
 
-if (!$Channel) { $Channel = 'master' }
+if (!$Channel) { $Channel = 'dev' }
 if (!$ToolsSource) { $ToolsSource = 'https://aspnetcore.blob.core.windows.net/buildtools' }
 
 # Execute

run.sh

@@ -248,7 +248,7 @@ if [ -f "$config_file" ]; then
     [ ! -z "${config_tools_source:-}" ] && tools_source="$config_tools_source"
 fi
 
-[ -z "$channel" ] && channel='master'
+[ -z "$channel" ] && channel='dev'
 [ -z "$tools_source" ] && tools_source='https://aspnetcore.blob.core.windows.net/buildtools'
 
 get_korebuild