add backport for proxmox

hosts

@@ -4,7 +4,7 @@ all:
     ubuntu:
       hosts:
         hindley.adh.auro.re:
-    debian-buster:
+    debian_buster:
       hosts:
         azerty.fil.sand.auro.re:
         dns-histausse.fil.sand.auro.re:
@@ -12,7 +12,7 @@ all:
         vm1:
         vm2:
         vm3:
-    proxmox:
+    proxmox_buster:
       hosts:
         hellman.fil.sand.auro.re:
     proxy:
@@ -38,3 +38,4 @@ all:
       hosts:
         azerty.fil.sand.auro.re:
         hindley.adh.auro.re:
+        hellman.fil.sand.auro.re:

roles/vpn/tasks/main.yml

@@ -3,4 +3,4 @@
   apt_repository:
     repo: deb http://deb.debian.org/debian buster-backports main
     state: present
-  when: "'debian-buster' in group_names"
+  when: "'debian_buster' in group_names or 'proxmox_buster' in group_names"