Always install gpg for nginx apt repo

Change-Id: I0c3a5f58b79836439e1031b031a4e46f18fcbf93
diff --git a/tasks/Debian.yml b/tasks/Debian.yml
index eebc077..3d1d8e8 100644
--- a/tasks/Debian.yml
+++ b/tasks/Debian.yml
@@ -4,6 +4,12 @@
 # SPDX-FileCopyrightText: © 2020 Open Networking Foundation <support@opennetworking.org>
 # SPDX-License-Identifier: Apache-2.0
 
+- name: Install GPG to support adding apt repo keys
+  apt:
+    name: "gpg"
+    state: "present"
+    update_cache: true
+
 # Docs: http://nginx.org/en/linux_packages.html
 - name: Add NGINX apt repo key
   apt_key: