Update plugin com.google.protobuf to v0.9.4 (#935)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

build.gradle

@@ -17,7 +17,7 @@ buildscript {
         guavaVersion = '32.1.1-jre'
         // https://github.com/protocolbuffers/protobuf/releases
         protobufVersion = '3.23.4'
-        protobufGradlePluginVersion = '0.9.3'
+        protobufGradlePluginVersion = '0.9.4'
 
         // https://github.com/spring-projects/spring-boot/releases
         springBootVersion = '2.7.13'