Add Salt baseline states for Proxmox Mail Gateway.

Co-authored-by: Cursor <cursoragent@cursor.com>

pmg/auto_updates.sls

@@ -0,0 +1,28 @@
+pmg-updates-packages:
+  pkg.installed:
+    - pkgs:
+      - unattended-upgrades
+      - apt-listchanges
+
+pmg-apt-auto-upgrades:
+  file.managed:
+    - name: /etc/apt/apt.conf.d/20auto-upgrades
+    - source: salt://pmg/files/20auto-upgrades.jinja
+    - template: jinja
+    - user: root
+    - group: root
+    - mode: '0644'
+
+pmg-unattended-policy:
+  file.managed:
+    - name: /etc/apt/apt.conf.d/50unattended-upgrades
+    - source: salt://pmg/files/50unattended-upgrades.jinja
+    - template: jinja
+    - user: root
+    - group: root
+    - mode: '0644'
+
+pmg-unattended-service:
+  service.running:
+    - name: unattended-upgrades
+    - enable: true