Rename master to main in the release group docs

doc/ci/examples/deployment/index.md

@@ -69,7 +69,7 @@ staging:
     - gem install dpl
     - dpl --provider=heroku --app=my-app-staging --api_key=$HEROKU_STAGING_API_KEY
   only:
-    - master
+    - main
 ```
 
 The first line `apt-get update -yq` updates the list of available packages,
@@ -81,7 +81,7 @@ The above example is valid for all Debian-compatible systems.
 It's pretty common in the development workflow to have staging (development) and
 production environments
 
-Let's consider the following example: we would like to deploy the `master`
+Let's consider the following example: we would like to deploy the `main`
 branch to `staging` and all tags to the `production` environment.
 The final `.gitlab-ci.yml` for that setup would look like this:
 
@@ -92,7 +92,7 @@ staging:
     - gem install dpl
     - dpl --provider=heroku --app=my-app-staging --api_key=$HEROKU_STAGING_API_KEY
   only:
-    - master
+    - main
 
 production:
   stage: deploy
@@ -105,7 +105,7 @@ production:
 
 We created two deploy jobs that are executed on different events:
 
-- `staging`: Executed for all commits pushed to the `master` branch
+- `staging`: Executed for all commits pushed to the `main` branch
 - `production`: Executed for all pushed tags
 
 We also use two secure variables:

doc/user/project/pages/introduction.md

@@ -118,7 +118,7 @@ pages:
     paths:
       - public
   only:
-    - master
+    - main
 ```
 
 ### `.gitlab-ci.yml` for a static site generator
@@ -133,7 +133,7 @@ the `pages` job with the [`only` parameter](../../../ci/yaml/index.md#only--exce
 whenever a new commit is pushed to a branch used specifically for your
 pages.
 
-That way, you can have your project's code in the `master` branch and use an
+That way, you can have your project's code in the `main` branch and use an
 orphan branch (let's name it `pages`) to host your static generator site.
 
 You can create a new empty branch like this:
@@ -163,7 +163,7 @@ pages:
     - pages
 ```
 
-See an example that has different files in the [`master` branch](https://gitlab.com/pages/jekyll-branched/tree/master)
+See an example that has different files in the [`main` branch](https://gitlab.com/pages/jekyll-branched/tree/main)
 and the source files for Jekyll are in a [`pages` branch](https://gitlab.com/pages/jekyll-branched/tree/pages) which
 also includes `.gitlab-ci.yml`.