feat(bigquery/storage/managedwriter): enable field name indirection

bigquery/storage/managedwriter/internal/annotations/annotations.proto

@@ -0,0 +1,26 @@
+syntax = "proto3";
+
+package google.cloud.bigquery.storage.v1;
+
+import "google/protobuf/descriptor.proto";
+
+option go_package = "cloud.google.com/go/bigquery/storage/managedwriter/internal/annotations;annotations";
+option java_package = "com.google.cloud.bigquery.storage.v1";
+option java_multiple_files = true;
+option java_outer_classname = "AnnotationsProto";
+
+extend google.protobuf.FieldOptions {
+  // Setting the column_name extension allows users to reference
+  // bigquery column independently of the field name in the protocol buffer
+  // message.
+  //
+  // The intended use of this annotation is to reference a destination column
+  // named using characters unavailable for protobuf field names (e.g. unicode
+  // characters).
+  //
+  // More details about BigQuery naming limitations can be found here:
+  // https://cloud.google.com/bigquery/docs/schemas#column_names
+  //
+  // This extension is currently experimental.
+  optional string column_name = 454943157;
+}