cpkg: add git username/email to allow push

vars/cpkg.groovy

@@ -34,6 +34,8 @@ def call(Map params = [:]) {
         sh("git merge ${currentRef}")
 
         if (!skipPush) {
+            sh("git config user.email '${gitEmail}'")
+            sh("git config user.username '${gitUsername}'")
             sh("git push")
         } else {
             println("Skipping push. Set skipPush param to 'true' to enable remote repository update.")