Switch docs previews to use main branch

.gitlab/ci/docs.gitlab-ci.yml

@@ -10,8 +10,8 @@
     # because some repos are private and CI_JOB_TOKEN cannot access files.
     # See https://gitlab.com/gitlab-org/gitlab/issues/191273
     GIT_DEPTH: 1
-    # By default, deploy the Review App using the `master` branch of the `gitlab-org/gitlab-docs` project
-    DOCS_BRANCH: master
+    # By default, deploy the Review App using the `main` branch of the `gitlab-org/gitlab-docs` project
+    DOCS_BRANCH: main
   environment:
     name: review-docs/mr-${CI_MERGE_REQUEST_IID}
     # DOCS_REVIEW_APPS_DOMAIN and DOCS_GITLAB_REPO_SUFFIX are CI variables

doc/ci/jobs/index.md

@@ -29,7 +29,7 @@ jobs, where each of the jobs executes a different command.
 Of course a command can execute code directly (`./configure;make;make install`)
 or run a script (`test.sh`) in the repository.
 
-Jobs are picked up by [runners](../runners/README.md) and executed within the
+Jobs are picked up by [runners](../runners/README.md) and executed in the
 environment of the runner. What is important is that each job is run
 independently from each other.
 

scripts/trigger-build

@@ -255,7 +255,7 @@ module Trigger
     end
 
     def ref
-      ENV['DOCS_BRANCH'] || 'master'
+      ENV['DOCS_BRANCH'] || 'main'
     end
 
     # `gitlab-org/gitlab-docs` pipeline trigger "Triggered from gitlab-org/gitlab 'review-docs-deploy' job"