message: build: Add example for bazel_remote_cache to ci docs
diff: @@ -70,6 +70,13 @@ For a debug version of the Envoy binary you can run:
  The build artifact can be found in `/tmp/envoy-docker-build/envoy/source/exe/envoy-debug` (or wherever
  `$ENVOY_DOCKER_BUILD_DIR` points).
  +To leverage a [bazel remote cache](https://github.com/envoyproxy/envoy/tree/master/bazel#advanced-caching-setup) add the http_remote_cache endpoint to
  +the BAZEL_BUILD_OPTIONS environment variable
  +
  +```bash
  +BAZEL_BUILD_OPTIONS='--remote_http_cache=http://127.0.0.1:28080' ./ci/run_envoy_docker.sh './ci/do_ci.sh bazel.release'
  +```
  +
  The `./ci/run_envoy_docker.sh './ci/do_ci.sh <TARGET>'` targets are:
  * `bazel.api` &mdash; build and run API tests under `-c fastbuild` with clang.
  