Missing FrankenPHP worker config file breaks production build

[bkosun]

The production build stage depends on the worker.Caddyfile, which was removed in PR #765, leading to a build failure:

 > [php frankenphp_prod 3/8] COPY --link frankenphp/worker.Caddyfile /etc/caddy/worker.Caddyfile:
------
failed to solve: failed to compute cache key: failed to calculate checksum of ref r6yo1oqnav3wtb94hnksnjnh2::vzkxztt98f9v6nyl9f91lnwnd: "/frankenphp/worker.Caddyfile": not found

symfony-docker/Dockerfile

Line 79 in 330ea24

COPY --link frankenphp/worker.Caddyfile /etc/caddy/worker.Caddyfile

https://github.com/dunglas/symfony-docker/pull/765/files#diff-1cf8ff1c456e1d1c1c4292f692f0b094d5a26407d02b2679f6cb5aeef40462e3