upgrade appinfo to v3

appinfo.yml

@@ -1,5 +1,11 @@
-mainunit: forgejo.service
-mainunitfile: forgejo.service.j2
+version: 3
+mainunit: forgejo
+enableunits:
+  - forgejo.service
+  - forgejo-watch-sshkeys.service
+plugins:
+  - type: builtin
+    name: backups_scheduled
 ports:
     - web
 templatefiles:
@@ -8,6 +14,8 @@ templatefiles:
   - src: forgejo-watch-sshkeys.j2
     dest: ~/forgejo-watch-sshkeys
     mode: "0755"
+  - src: forgejo.service.j2
+    dest: ~/.config/systemd/user/forgejo.service
   - src: forgejo-watch-sshkeys.service.j2
     dest: ~/.config/systemd/user/forgejo-watch-sshkeys.service
 exports: