fix: update go-eth2-client dependency and use spec.DataVersionFulu constant

Author: samcm

go.mod

@@ -2,7 +2,7 @@ module github.com/ethpandaops/checkpointz
 
 go 1.22
 
-replace github.com/attestantio/go-eth2-client => github.com/pk910/go-eth2-client v0.0.0-20250515124841-1d7c6ee326e4
+replace github.com/attestantio/go-eth2-client => github.com/attestantio/go-eth2-client v0.25.1-0.20250603065335-ce8ba1e2c627
 
 require (
 	github.com/attestantio/go-eth2-client v0.25.0

go.sum

@@ -1,3 +1,5 @@
+github.com/attestantio/go-eth2-client v0.25.1-0.20250603065335-ce8ba1e2c627 h1:UTmXrVrZfSJu2f2aHBBpWktCjhL7osEUE9Mewr90oe0=
+github.com/attestantio/go-eth2-client v0.25.1-0.20250603065335-ce8ba1e2c627/go.mod h1:fvULSL9WtNskkOB4i+Yyr6BKpNHXvmpGZj9969fCrfY=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/btcsuite/btcd/btcec/v2 v2.3.4 h1:3EJjcN70HCu/mwqlUsGK8GcNVyLVxFDlWurTXGPFfiQ=
@@ -155,8 +157,6 @@ github.com/onsi/gomega v1.10.1 h1:o0+MgICZLuZ7xjH7Vx6zS/zcu93/BEp1VwkIW1mEXCE=
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
 github.com/pk910/dynamic-ssz v0.0.4 h1:DT29+1055tCEPCaR4V/ez+MOKW7BzBsmjyFvBRqx0ME=
 github.com/pk910/dynamic-ssz v0.0.4/go.mod h1:b6CrLaB2X7pYA+OSEEbkgXDEcRnjLOZIxZTsMuO/Y9c=
-github.com/pk910/go-eth2-client v0.0.0-20250515124841-1d7c6ee326e4 h1:riGVTN/A3PQsSD1+D0PM0s5QQuP8ksPTV5mKhiPmLlA=
-github.com/pk910/go-eth2-client v0.0.0-20250515124841-1d7c6ee326e4/go.mod h1:fvULSL9WtNskkOB4i+Yyr6BKpNHXvmpGZj9969fCrfY=
 github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=

pkg/api/handler.go

@@ -204,7 +204,7 @@ func (h *Handler) handleEthV2BeaconBlocks(ctx context.Context, r *http.Request,
 			ContentTypeJSON: block.Electra.MarshalJSON,
 			ContentTypeSSZ:  block.Electra.MarshalSSZ,
 		})
-	case "fulu":
+	case spec.DataVersionFulu.String():
 		rsp = NewSuccessResponse(ContentTypeResolvers{
 			ContentTypeJSON: block.Fulu.MarshalJSON,
 			ContentTypeSSZ:  block.Fulu.MarshalSSZ,