Add a 30-second wait before running update script
- hopefully this will end contention for /var/lib/apt/lists/lock
diff --git a/packer/build-ubuntu.json b/packer/build-ubuntu.json
index 35c48a1..8bfbeac 100644
--- a/packer/build-ubuntu.json
+++ b/packer/build-ubuntu.json
@@ -33,6 +33,7 @@
     {
       "type":"shell",
       "execute_command":"{{.Vars}} sudo -E -S bash '{{.Path}}'",
+      "pause_before":"30s",
       "scripts":[
         "ubuntu/update.sh"
       ]