chore: copy vendor/cache files

This is required to install Jetbrains versions of debugging gems debase and ruby-debug-ide

Dockerfile

@@ -20,4 +20,5 @@ RUN /app/bootstrap-app-dir.sh
 USER nexus
 WORKDIR /app
 COPY --chown=nexus:nexus Gemfile Gemfile.lock ./
+COPY vendor/cache ./vendor/cache/
 RUN /app/bootstrap-app-bundle.sh