Reference PR build for protobuf plugin

Temporary fix until the PR against the protobuf plugin at
google/protobuf-gradle-plugin#786
is merged.

Author: breskeby

x-pack/plugin/otel-data/build.gradle

@@ -6,14 +6,28 @@
  */
 import org.elasticsearch.gradle.transform.UnzipTransform
 import com.google.protobuf.gradle.GenerateProtoTask
+
+buildscript {
+  repositories {
+    maven { url = "https://jitpack.io" }
+  }
+  dependencies {
+    classpath 'com.github.google:protobuf-gradle-plugin:PR786-SNAPSHOT'
+  }
+}
+
 plugins {
   id 'elasticsearch.internal-es-plugin'
   id 'elasticsearch.internal-yaml-rest-test'
   id 'elasticsearch.internal-java-rest-test'
   id 'elasticsearch.internal-cluster-test'
-  id('com.google.1protobuf') version '0.9.5'
+  // We rely on a snapshot including a fix for 9.1 compatibility.
+  // See https://github.com/google/protobuf-gradle-plugin/pull/786
+  //  id('com.google.protobuf') version '0.9.5'
 }
 
+apply plugin:"com.google.protobuf"
+
 esplugin {
   name = 'x-pack-otel-data'
   description = 'The OTEL plugin defines OTEL data streams and ingest pipelines.'