build: modifies vit-ss to use env variables for db/service version (#180)

Author: jmgilman

nix/vit-servicing-station/operables.nix

@@ -55,7 +55,8 @@
           inherit package;
           args = {
             "--in-settings-file" = configFile;
-            "--service-version" = "3.4";
+            "--service-version" = "$VERSION";
+            "--db-url" = "$DB_URL";
           };
         };
     };