chore(caddy): bump github.com/dunglas/mercure/caddy in /caddy

Bumps [github.com/dunglas/mercure/caddy](https://github.com/dunglas/mercure) from 0.15.5 to 0.15.6.
- [Release notes](https://github.com/dunglas/mercure/releases)
- [Changelog](https://github.com/dunglas/mercure/blob/main/.goreleaser.yml)
- [Commits](dunglas/mercure@v0.15.5...v0.15.6)

---
updated-dependencies:
- dependency-name: github.com/dunglas/mercure/caddy
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

caddy/go.mod

@@ -10,7 +10,7 @@ require (
 	github.com/caddyserver/caddy/v2 v2.7.6
 	github.com/caddyserver/certmagic v0.20.0
 	github.com/dunglas/frankenphp v1.0.0
-	github.com/dunglas/mercure/caddy v0.15.5
+	github.com/dunglas/mercure/caddy v0.15.6
 	github.com/dunglas/vulcain/caddy v1.0.0
 	github.com/spf13/cobra v1.8.0
 	go.uber.org/automaxprocs v1.5.3
@@ -29,7 +29,6 @@ require (
 	github.com/RoaringBitmap/roaring v1.6.0 // indirect
 	github.com/alecthomas/chroma/v2 v2.12.0 // indirect
 	github.com/antlr/antlr4/runtime/Go/antlr/v4 v4.0.0-20230305170008-8188dc5388df // indirect
-	github.com/antlr4-go/antlr/v4 v4.13.0 // indirect
 	github.com/aryann/difflib v0.0.0-20210328193216-ff5ff6dc229b // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/bits-and-blooms/bitset v1.11.0 // indirect
@@ -44,14 +43,13 @@ require (
 	github.com/dgryski/go-farm v0.0.0-20200201041132-a6ae2369ad13 // indirect
 	github.com/dlclark/regexp2 v1.10.0 // indirect
 	github.com/dunglas/httpsfv v1.0.2 // indirect
-	github.com/dunglas/mercure v0.15.5 // indirect
+	github.com/dunglas/mercure v0.15.6 // indirect
 	github.com/dunglas/vulcain v1.0.0 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/fsnotify/fsnotify v1.7.0 // indirect
 	github.com/fxamacker/cbor/v2 v2.5.0 // indirect
 	github.com/getkin/kin-openapi v0.120.0 // indirect
-	github.com/go-chi/chi v4.1.2+incompatible // indirect
 	github.com/go-chi/chi/v5 v5.0.10 // indirect
 	github.com/go-kit/kit v0.13.0 // indirect
 	github.com/go-kit/log v0.2.1 // indirect
@@ -104,7 +102,6 @@ require (
 	github.com/matttproud/golang_protobuf_extensions/v2 v2.0.0 // indirect
 	github.com/mgutz/ansi v0.0.0-20200706080929-d51e80ef957d // indirect
 	github.com/mholt/acmez v1.2.0 // indirect
-	github.com/micromdm/scep/v2 v2.2.0 // indirect
 	github.com/miekg/dns v1.1.57 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/go-ps v1.0.0 // indirect
@@ -157,7 +154,6 @@ require (
 	github.com/yuin/goldmark-highlighting/v2 v2.0.0-20230729083705-37449abec8cc // indirect
 	github.com/zeebo/blake3 v0.2.3 // indirect
 	go.etcd.io/bbolt v1.3.8 // indirect
-	go.mozilla.org/pkcs7 v0.0.0-20210826202110-33d05740a352 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.45.0 // indirect
 	go.opentelemetry.io/contrib/propagators/autoprop v0.45.0 // indirect
 	go.opentelemetry.io/contrib/propagators/aws v1.20.0 // indirect