Updates remaining master references to main (#2228)

- Also updated the branch config for the monthly trigger in https://app.circleci.com/settings/project/github/gruntwork-io/docs/triggers

Author: oredavids

Diff for: .circleci/config.yml

@@ -99,14 +99,14 @@ references:
 
   notify_slack_staging: &notify_slack_staging
     slack/status:
-      failure_message: "[Docs] :red_circle: $CIRCLE_JOB has failed on master! Build triggered by: $CIRCLE_USERNAME. You have one hour to fix or revert!!"
+      failure_message: "[Docs] :red_circle: $CIRCLE_JOB has failed on main! Build triggered by: $CIRCLE_USERNAME. You have one hour to fix or revert!!"
       success_message: ":tada: [Stage] Docs site has been successfully deployed at version $CIRCLE_SHA1 to https://docs.dogfood-stage.com"
-      only_for_branches: "master"
+      only_for_branches: "main"
       channel: "C01J73HUKEF" # #team-platform-notifications
 
   notify_slack_prod: &notify_slack_prod
     slack/status:
-      failure_message: "[Docs] :red_circle: $CIRCLE_JOB has failed on master! Build triggered by: $CIRCLE_USERNAME. You have one hour to fix or revert!!"
+      failure_message: "[Docs] :red_circle: $CIRCLE_JOB has failed on main! Build triggered by: $CIRCLE_USERNAME. You have one hour to fix or revert!!"
       success_message: ":tada: [Prod] Docs site has been successfully deployed at version $CIRCLE_TAG to https://docs.gruntwork.io"
       channel: "C01J73HUKEF" # #team-platform-notifications
 
@@ -217,7 +217,7 @@ workflows:
       - validate-build:
           filters:
             branches:
-              ignore: master
+              ignore: main
   stage_deployment:
     # Make sure this pipeline doesn't run when a schedule is triggered
     when:
@@ -229,7 +229,7 @@ workflows:
       - validate-build:
           filters:
             branches:
-              only: master
+              only: main
       - deploy-to-stage:
           context:
             - SLACK__WEBHOOK__team-platform
@@ -239,7 +239,7 @@ workflows:
             - validate-build
           filters:
             branches:
-              only: master
+              only: main
   prod_deployment:
     # Make sure this pipeline doesn't run when a schedule is triggered
     when: