Use main as default branch (#162)

http://b/188715321

Author: Philmod

Jenkinsfile

@@ -1,4 +1,4 @@
-String cron_string = BRANCH_NAME == "master" ? "H 12 * * 1,3" : ""
+String cron_string = BRANCH_NAME == "main" ? "H 12 * * 1,3" : ""
 
 pipeline {
   agent { label 'ephemeral-linux' }
@@ -14,11 +14,11 @@ pipeline {
     GIT_COMMIT_SUBJECT = sh(returnStdout: true, script:"git log --format=%s -n 1 HEAD").trim()
     GIT_COMMIT_AUTHOR = sh(returnStdout: true, script:"git log --format='%an' -n 1 HEAD").trim()
     GIT_COMMIT_SUMMARY = "`<https://github.com/Kaggle/docker-rstats/commit/${GIT_COMMIT}|${GIT_COMMIT_SHORT}>` ${GIT_COMMIT_SUBJECT} - ${GIT_COMMIT_AUTHOR}"
-    SLACK_CHANNEL = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"master\" ]]; then echo \"#kernelops\"; else echo \"#builds\"; fi").trim()
+    SLACK_CHANNEL = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"main\" ]]; then echo \"#kernelops\"; else echo \"#builds\"; fi").trim()
     // See b/152450512
     GITHUB_PAT = credentials('github-pat')
-    PRETEST_TAG = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"master\" ]]; then echo \"ci-pretest\"; else echo \"${GIT_BRANCH}-pretest\"; fi").trim()
-    STAGING_TAG = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"master\" ]]; then echo \"staging\"; else echo \"${GIT_BRANCH}-staging\"; fi").trim()
+    PRETEST_TAG = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"main\" ]]; then echo \"ci-pretest\"; else echo \"${GIT_BRANCH}-pretest\"; fi").trim()
+    STAGING_TAG = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"main\" ]]; then echo \"staging\"; else echo \"${GIT_BRANCH}-staging\"; fi").trim()
   }
 
   stages {