ubuntu.sh: install packer for temporary

In order to  create an AMI for staging build node "Test Jenkins AMI",
the tool "packer" is needed.

Signed-off-by: Arthur She <arthur.she@linaro.org>
Change-Id: Iadab3822649e47144d2872cf5192e2f282da1712
diff --git a/ubuntu.sh b/ubuntu.sh
index 39c6fa3..5f080a2 100755
--- a/ubuntu.sh
+++ b/ubuntu.sh
@@ -49,5 +49,10 @@
 systemctl disable unattended-upgrades.service
 apt-get -y remove unattended-upgrades
 
+# Install packer temporary
+wget -O- https://apt.releases.hashicorp.com/gpg | gpg --dearmor | sudo tee /usr/share/keyrings/hashicorp-archive-keyring.gpg
+echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list
+apt-get update && apt-get -y install packer
+
 sed -i -e 's/#PermitTTY.*/PermitTTY yes/g' /etc/ssh/sshd_config