feat: adopt inclusive language - main default branch

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

[RFC]: artsy/README#427

.circleci/config.yml

@@ -271,7 +271,7 @@ jobs:
             git config user.name "Hokusai CI"
             git config user.email "it@artsymail.com"
             git commit -am "Release Hokusai $VERSION"
-            git push origin master
+            git push origin main
 
             cd /tmp
             rm -f hokusai-$VERSION-Darwin-x86_64.tar.gz
@@ -307,35 +307,35 @@ workflows:
             - test_integration
           filters:
             branches:
-              only: master
+              only: main
       - release_beta3_linux:
           requires:
             - test_linux3
             - test_integration
           filters:
             branches:
-              only: master
+              only: main
       - release_beta_macos:
           requires:
             - test_macos2
             - test_integration
           filters:
             branches:
-              only: master
+              only: main
       - release_beta3_macos:
           requires:
             - test_macos3
             - test_integration
           filters:
             branches:
-              only: master
+              only: main
       - release_beta_dockerhub:
           requires:
             - test_linux2
             - test_integration
           filters:
             branches:
-              only: master
+              only: main
       - release_version_linux:
           filters:
             branches:

README.md

@@ -1,4 +1,4 @@
-## HOKUSAI [![CircleCI](https://circleci.com/gh/artsy/hokusai/tree/master.svg?style=svg)](https://circleci.com/gh/artsy/hokusai/tree/master)
+## HOKUSAI [![CircleCI](https://circleci.com/gh/artsy/hokusai/tree/main.svg?style=svg)](https://circleci.com/gh/artsy/hokusai/tree/main)
 
 <a href="https://en.wikipedia.org/wiki/Hokusai"><img height="300" src="hokusai.jpg"></a>
 
@@ -161,7 +161,7 @@ $ brew link --overwrite hokusai
 
 If you are on Linux:
 ```
-curl -sSL https://raw.githubusercontent.com/artsy/hokusai/master/get-hokusai.sh | sudo bash
+curl -sSL https://raw.githubusercontent.com/artsy/hokusai/main/get-hokusai.sh | sudo bash
 ```
 
 ### Alternate Installation Methods
@@ -181,7 +181,7 @@ curl --silent https://artsy-provisioning-public.s3.amazonaws.com/hokusai/hokusai
 ## Setup
 
 1. [Configure your AWS credentials](https://boto3.amazonaws.com/v1/documentation/api/latest/guide/configuration.html#configuring-credentials).
-1. Run `hokusai configure --kubectl-version <kubectl version> --s3-bucket <bucket name> --s3-key <file key>`. You'll need to provide the kubectl version matching your Kubernetes deployments, as well as the S3 bucket name and key of your org's kubectl config file. System administrators: see [Administering Hokusai](./docs/Administering_Hokusai.md) for instructions on preparing AWS, Kubernetes, and publishing a kubectl config file. Artsy devs: see [these artsy/README docs](https://github.com/artsy/README/blob/master/playbooks/hokusai.md) for the current way to install and configure hokusai.
+1. Run `hokusai configure --kubectl-version <kubectl version> --s3-bucket <bucket name> --s3-key <file key>`. You'll need to provide the kubectl version matching your Kubernetes deployments, as well as the S3 bucket name and key of your org's kubectl config file. System administrators: see [Administering Hokusai](./docs/Administering_Hokusai.md) for instructions on preparing AWS, Kubernetes, and publishing a kubectl config file. Artsy devs: see [these artsy/README docs](https://github.com/artsy/README/blob/main/playbooks/hokusai.md) for the current way to install and configure hokusai.
 
 To enable bash autocompletion: `eval "$(_HOKUSAI_COMPLETE=source hokusai)"`
 
@@ -230,9 +230,9 @@ Full details are in the [Review App reference](./docs/Review_Apps.md).
 
 ## Distributing Hokusai
 
-Merges to master automatically distribute Pyinstaller versions for beta testing at https://artsy-provisioning-public.s3.amazonaws.com/hokusai/hokusai-beta-Darwin-x86_64 and https://artsy-provisioning-public.s3.amazonaws.com/hokusai/hokusai-beta-Linux-x86_64 respectively.
+Merges to main automatically distribute Pyinstaller versions for beta testing at https://artsy-provisioning-public.s3.amazonaws.com/hokusai/hokusai-beta-Darwin-x86_64 and https://artsy-provisioning-public.s3.amazonaws.com/hokusai/hokusai-beta-Linux-x86_64 respectively.
 
-To create a new release, bump the version by editing the `./hokusai VERSION` file, create an entry in CHANGELOG.md and open a PR from `master` to the `release` branch of this repo.
+To create a new release, bump the version by editing the `./hokusai VERSION` file, create an entry in CHANGELOG.md and open a PR from `main` to the `release` branch of this repo.
 
 ## The Name
 
@@ -256,8 +256,8 @@ You can learn more about this work from [our blog][footer_blog] and by following
 our [job postings][footer_jobs]!
 
 [footer_website]: https://www.artsy.net/
-[footer_principles]: https://github.com/artsy/README/blob/master/culture/engineering-principles.md
-[footer_open]: https://github.com/artsy/README/blob/master/culture/engineering-principles.md
+[footer_principles]: https://github.com/artsy/README/blob/main/culture/engineering-principles.md
+[footer_open]: https://github.com/artsy/README/blob/main/culture/engineering-principles.md
 [footer_blog]: https://artsy.github.io/
 [footer_twitter]: https://twitter.com/ArtsyOpenSource
 [footer_api]: https://developers.artsy.net/