tiny module to export monitoring metrics for Prometheus

 Prometheus::Tiny is a minimal metrics client for the Prometheus time-series
 database, that can be used to instrument a service so that it can export
 monitoring metrics so that Prometheus compatible servers can collect them.
 .
 It does the following things differently to Net::Prometheus:
  * No setup. No need to pre-declare metrics to get something useful.
  * Labels are passed in a hash. Positional parameters get awkward.
  * No inbuilt collectors, PSGI apps, etc. Just the metrics.
  * No different metric types. You get what you ask for.