Correct web build script in CI

.gitlab-ci.yml

@@ -40,7 +40,7 @@ build-web:
   stage: build
   <<: *cache_directive
   script:
-    - cargo build --release -p game_core --target x86_64-unknown-linux-gnu
+    - cd "${CI_PROJECT_DIR}/game_core" && trunk build --release
   only:
     - trunk