Update module github.com/grpc-ecosystem/grpc-gateway/v2 to v2.26.3

Author: renovate[bot]

example/otel-collector/go.mod

@@ -21,7 +21,7 @@ require (
 	github.com/go-logr/logr v1.4.2 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/google/uuid v1.6.0 // indirect
-	github.com/grpc-ecosystem/grpc-gateway/v2 v2.26.1 // indirect
+	github.com/grpc-ecosystem/grpc-gateway/v2 v2.26.3 // indirect
 	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.34.0 // indirect
 	go.opentelemetry.io/otel/metric v1.34.0 // indirect