Update plugin protobuf to v0.9.4

Author: renovate[bot]

gradle/libs.versions.toml

@@ -28,4 +28,4 @@ defaults = { id = "io.github.sgtsilvio.gradle.defaults", version = "0.2.0" }
 hivemq-extension = { id = "com.hivemq.extension", version = "3.2.0" }
 license = { id = "com.github.hierynomus.license", version = "0.16.1" }
 oci = { id = "io.github.sgtsilvio.gradle.oci", version = "0.16.0" }
-protobuf = { id = "com.google.protobuf", version = "0.9.2" }
+protobuf = { id = "com.google.protobuf", version = "0.9.4" }