Add `--fail` to the curl command to catch app 500 erros

# `nginx-sidecar` changelog

## 0.3.3

- Add `--fail` to the curl health check. This causes curl to return non-zero exit codes

  even if the http request completes but the response code represents an error.

- Add `--verbose` to the curl health check. This helps us debug any application responses

  if the server does start, but with errors.

## 0.3.2

- Use `$request_method` and `$request_uri` instead of the combined `$request`.

0.3.2

0.3.3

# Wait for the application to start before accepting ALB requests.

while sleep 2; do

  curl --max-time 5 http://app:${APP_PORT}${HEALTHCHECK_PATH:-/health} && break

  curl --verbose --fail --max-time 5 http://app:${APP_PORT}${HEALTHCHECK_PATH:-/health} && break

done

# run in foreground as pid 1