forgejo: fix ssh

really only a temporary solution for now, ideally we would do it so
only the forgejo user can use the .ssh/authorizedKeys file in their home
folder. but nix purity rules prevents that

modules/services/forgejo.nix

@@ -1,4 +1,4 @@
-{ config, pkgs, ... }:
+{ config, pkgs, lib, ... }:
 
 {
   services.forgejo = {
@@ -19,6 +19,11 @@
     };
   };
 
+  # forgejo has user keys under its own .ssh/authorizedKeys file.
+  # nix blocks me from using users.users.<name>.openssh.authorizedKeys.keyFiles
+  # in order to only allow that to the forgejo user as it has "/var"
+  services.openssh.authorizedKeysInHomedir = lib.mkForce true;
+
   services.caddy.virtualHosts."git.${config.homelab.domain}" = {
     useACMEHost = config.homelab.domain;
     extraConfig = ''