fix(dart_frog_prod_server): copy static assets into docker image (#352)

Author: felangel

bricks/dart_frog_prod_server/__brick__/build/Dockerfile

@@ -22,6 +22,7 @@ RUN dart compile exe bin/server.dart -o bin/server
 FROM scratch
 COPY --from=build /runtime/ /
 COPY --from=build /app/bin/server /app/bin/
+{{#serveStaticFiles}}COPY --from=build /app/public /public/{{/serveStaticFiles}}
 
 # Start server.
 CMD ["/app/bin/server"]