Rename primary branch to main (#130)

.github/PULL_REQUEST_TEMPLATE.md

@@ -2,13 +2,13 @@
 Thank you for submitting a pull request!
 
 Please verify that:
-* [ ] Code is up-to-date with the `master` branch.
+* [ ] Code is up-to-date with the `main` branch.
 * [ ] You've successfully built and run the tests locally.
   https://github.com/ExpediaGroup/mittens#how-to-build-and-run
 * [ ] There are new or updated unit tests validating the change.
 
 Refer to CONTRIBUTING.md for more details.
-  https://github.com/ExpediaGroup/mittens/blob/master/CONTRIBUTING.md
+  https://github.com/ExpediaGroup/mittens/blob/main/CONTRIBUTING.md
 -->
 
 ### :pencil: Description

.github/workflows/gh-pages.yml

@@ -3,7 +3,7 @@ name: Publish Docs
 on:
   push:
     branches:
-      - master
+      - main
     paths:
       - 'docs/**'
       - 'website/**'

.github/workflows/go.yml

@@ -3,10 +3,10 @@ name: Build
 on:
   pull_request:
     branches:
-      - master
+      - main
   push:
     branches:
-      - master
+      - main
 
 jobs:
 

docs/installation/building.md

@@ -4,7 +4,7 @@ title: How to Build
 ---
 
 Mittens is written in Go and uses [Go Modules](https://github.com/golang/go/wiki/Modules). 
-We provide a [Makefile](https://github.com/ExpediaGroup/mittens/blob/master/Makefile) which can be used to generate an executable binary and a Dockerfile if you prefer to run using Docker.
+We provide a [Makefile](https://github.com/ExpediaGroup/mittens/blob/main/Makefile) which can be used to generate an executable binary and a Dockerfile if you prefer to run using Docker.
 
 ### Binary