Log Message:
caddy: update to 2.7.5

Now works with Go 1.21.

NB: I removed the Illumos listener patches, it looks like they are no longer
required -- I hope that's correct.

In this release, we've fixed quite a few small bugs and annoyances, including
HTTP/2 Rapid Reset which affected most HTTP/2 implementations.

- Updated https://github.com/quic-go/quic-go from v0.37.5 to v0.39.0, including
  many performance improvements. GSO and ECN are now enabled by default, but you
  may turn them off by setting the QUIC_GO_DISABLE_GSO=true and
  QUIC_GO_DISABLE_ECN=true environment variables respectively, if they cause you
  problems. See the quic-go release notes for more details.
- The file server's fileserver.BrowseTemplate is now exported, so it may be
  customized by programs embedding Caddy.
- Environment variables loaded with --envfile no longer override existing
  variables.
- The encode handler now compresses application/wasm* content types by
  default.
- The reverse_proxy handler can now emit very detailed logs for debugging
  streaming and buffering. To enable it, set the verbose_logs subdirective, and
  set logging to debug level. Since the logs from this are very noisy, using
  verbose_logs to opt-in is necessary. We may ask you to enable this when asking
  for support!
- You can now check the version with caddy -v, like most other CLI utilities!