Bump com.google.protobuf

Bumps com.google.protobuf from 0.8.7 to 0.9.4.

---
updated-dependencies:
- dependency-name: com.google.protobuf
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

samples/lambda-kotlin-request-router-sample-proto/build.gradle.kts

@@ -20,7 +20,7 @@ plugins {
     idea
     id("com.github.johnrengelman.shadow") version "5.1.0"
     id("org.jmailen.kotlinter") version "4.3.0"
-    id("com.google.protobuf") version "0.8.7"
+    id("com.google.protobuf") version "0.9.4"
 }