[terraform] Deploy Tunnelbroker 0.16 to staging

Summary: Deploying the newest version of service.

Test Plan: Run `terraform plan -target aws_ecs_service.tunnelbroker`

Reviewers: bartek, tomek, marcin

Reviewed By: marcin

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D13279

services/terraform/remote/service_tunnelbroker.tf

@@ -1,7 +1,7 @@
 locals {
   tunnelbroker_config = {
     docker_image = "commapp/tunnelbroker"
-    docker_tag   = local.is_staging ? "0.15-staging" : "0.14"
+    docker_tag   = local.is_staging ? "0.16-staging" : "0.14"
 
     grpc_port      = 50051
     websocket_port = 51001