add histogram

Signed-off-by: Jay DeLuca <jaydeluca4@gmail.com>

Author: jaydeluca

prometheus-metrics-exporter-opentelemetry/src/test/java/io/prometheus/metrics/exporter/opentelemetry/ExportTest.java

@@ -312,6 +312,7 @@ void metricsWithoutDataPointsAreNotExported() {
     Counter.builder().name("counter_no_data").labelNames("pool").register(registry);
     Gauge.builder().name("gauge_no_data").labelNames("pool").register(registry);
     Summary.builder().name("summary_no_data").labelNames("pool").register(registry);
+    Histogram.builder().name("histogram_no_data").labelNames("pool").register(registry);
     StateSet.builder()
         .name("stateset_no_data")
         .states("state")