Merge pull request #44332 from jerith666/restic-s3-default

restic: add missing default for s3CredentialsFile

nixos/modules/services/backup/restic.nix

···
 
         s3CredentialsFile = mkOption {
           type = with types; nullOr str;
+          default = null;
           description = ''
             file containing the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY
             for an S3-hosted repository, in the format of an EnvironmentFile