feat: adopt inclusive language - main default branch

Favor inclusive language in the codebase per this [RFC][].

[RFC]: artsy/README#427

.circleci/config.yml

@@ -10,11 +10,11 @@ not_staging_or_release: &not_staging_or_release
         - staging
         - release
 
-only_master: &only_master
+only_main: &only_main
   context: hokusai
   filters:
     branches:
-      only: master
+      only: main
 
 only_release: &only_release
   context: hokusai
@@ -33,12 +33,12 @@ workflows:
       # staging
       - hokusai/push:
           name: push-staging-image
-          <<: *only_master
+          <<: *only_main
           requires:
             - test
 
       - hokusai/deploy-staging:
-          <<: *only_master
+          <<: *only_main
           project-name: apr-dashboard
           requires:
             - push-staging-image

README.md

@@ -10,7 +10,7 @@ APRd (aka. APR dashboard), is a real-time dashboard built in [Elixir](https://el
 - Production: https://aprd.artsy.net
 - Staging: https://aprd-staging.artsy.net
 - GitHub: https://github.com/artsy/aprd/
-- CI: [CircleCI](https://circleci.com/gh/artsy/apr-dashboard); merged PRs to artsy/apr-dashboard#master are automatically deployed to staging. PRs from `staging` to `release` are automatically deployed to production. [Start a deploy...](https://github.com/artsy/apr-dashboard/compare/release...staging?expand=1)
+- CI: [CircleCI](https://circleci.com/gh/artsy/apr-dashboard); merged PRs to artsy/apr-dashboard#main are automatically deployed to staging. PRs from `staging` to `release` are automatically deployed to production. [Start a deploy...](https://github.com/artsy/apr-dashboard/compare/release...staging?expand=1)
 - Point People: [@jpotts244](https://github.com/jpotts244) [@kajatiger](https://github.com/kajatiger)
 
 ## Clone the project

bin/setup

@@ -1,7 +1,7 @@
 #!/bin/bash
 
 # This assumes you have general prerequisites installed as by:
-# https://github.com/artsy/potential/blob/master/scripts/setup
+# https://github.com/artsy/potential/blob/main/scripts/setup
 
 # Exit if any subcommand fails
 set -e

lib/apr/views/commerce/commerce_error_slack_view.ex

@@ -1,4 +1,4 @@
-# https://github.com/artsy/exchange/blob/master/app/events/application_error_event.rb
+# https://github.com/artsy/exchange/blob/main/app/events/application_error_event.rb
 
 defmodule Apr.Views.CommerceErrorSlackView do
   import Apr.Views.Helper

lib/apr/views/commerce/commerce_order_slack_view.ex

@@ -1,4 +1,4 @@
-# https://github.com/artsy/exchange/blob/master/app/events/order_event.rb
+# https://github.com/artsy/exchange/blob/main/app/events/order_event.rb
 defmodule Apr.Views.CommerceOrderSlackView do
   @payments Application.get_env(:apr, :payments)