Migrate keygrip extraction into jenkins

Change-Id: Ibfe43bd657153731b1c080a56b8f4bdc7d4a71f1
diff --git a/cicd/pipelines/tasks/task_publish_unstable.jenkins b/cicd/pipelines/tasks/task_publish_unstable.jenkins
index b5a7e80..829eedd 100644
--- a/cicd/pipelines/tasks/task_publish_unstable.jenkins
+++ b/cicd/pipelines/tasks/task_publish_unstable.jenkins
@@ -14,6 +14,19 @@
     return sh(returnStdout: true, script: "cat ${filename}").trim()
 }
 
+String getKeygripId() {
+    def script = """
+        gpg --no-default-keyring \
+            --keyring=release-keyring.gpg \
+            --with-colons \
+            --list-secret-keys \                                                                                                          
+        | awk -F: '$1 == "grp" { print $10 }' \                                                                                       
+        | head -n1
+    """
+
+    return sh(returnStdout: true, script: script).trim()
+}
+
 def workspacePath = "/home/jenkins/workspace"
 def buildLabel = "task.publish.unstable-${UUID.randomUUID().toString()}"
 def sourcePath = "${workspacePath}/src"
@@ -40,7 +53,7 @@
                     def debianMirrorSnapshotName = getLatestSnapshot('debian-buster')
                     def coreSnapshotName = getLatestSnapshot('core-unstable')
                     def bspSnapshotName  = getLatestSnapshot('enterprise-bsp-unstable')
-                    def keygripId = getFileContents('/var/lib/aptly/keyring/keygrip.txt')
+                    def keygripId = getKeygripId()
 
                     def date = new Date()
                     String stamp = date.format("yyyyMMdd-HHmmss")