Escape backslash Jenkinsfile (#1353)

Author: rosbo

Jenkinsfile

@@ -16,8 +16,8 @@ pipeline {
     GIT_COMMIT_SUMMARY = "`<https://github.com/Kaggle/docker-python/commit/${GIT_COMMIT}|${GIT_COMMIT_SHORT}>` ${GIT_COMMIT_SUBJECT} - ${GIT_COMMIT_AUTHOR}"
     MATTERMOST_CHANNEL = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"main\" ]]; then echo \"#kernelops\"; else echo \"#builds\"; fi").trim()
     // Use dev branch names as tags, but replace '/' with '-' using sed since docker images don't support forward slash
-    PRETEST_TAG = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"main\" ]]; then echo \"ci-pretest\"; else echo \"${GIT_BRANCH}-pretest\" | sed 's/\//-/g'; fi").trim()
-    STAGING_TAG = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"main\" ]]; then echo \"staging\"; else echo \"${GIT_BRANCH}-staging\" | sed 's/\//-/g'; fi").trim()
+    PRETEST_TAG = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"main\" ]]; then echo \"ci-pretest\"; else echo \"${GIT_BRANCH}-pretest\" | sed 's/\\//-/g'; fi").trim()
+    STAGING_TAG = sh(returnStdout: true, script: "if [[ \"${GIT_BRANCH}\" == \"main\" ]]; then echo \"staging\"; else echo \"${GIT_BRANCH}-staging\" | sed 's/\\//-/g'; fi").trim()
   }
 
   stages {