tests: Add Ubuntu 16.04 to image_prep inventory

moreati · moreati · commit 64a581b2aced · 2025-12-02T13:06:05.000Z
I missed this when committing what built 2025.02 iamges
diff --git a/tests/image_prep/hosts.ini b/tests/image_prep/hosts.ini
@@ -43,6 +43,7 @@ centos7
 centos8
 debian9
 debian10
+ubuntu1604
 ubuntu1804
 
 [ansible_11]
