[Metrics] Update default buckets for Explicit Bucket Histogram from spec

docs/metrics/customizing-the-sdk/README.md

@@ -235,8 +235,7 @@ with the metric are of interest to you.
 #### Specify custom boundaries for Histogram
 
 By default, the boundaries used for a Histogram are [`{ 0, 5, 10, 25, 50, 75,
-100, 250, 500,
-1000}`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#explicit-bucket-histogram-aggregation).
+100, 250, 500,750, 1000, 2500, 5000, 7500, 10000}`](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#explicit-bucket-histogram-aggregation).
 Views can be used to provide custom boundaries for a Histogram. The measurements
 are then aggregated using the custom boundaries provided instead of the the
 default boundaries. This requires the use of

src/OpenTelemetry/Metrics/Metric.cs

@@ -25,7 +25,7 @@ namespace OpenTelemetry.Metrics
     /// </summary>
     public sealed class Metric
     {
-        internal static readonly double[] DefaultHistogramBounds = new double[] { 0, 5, 10, 25, 50, 75, 100, 250, 500, 1000 };
+        internal static readonly double[] DefaultHistogramBounds = new double[] { 0, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000 };
 
         private readonly AggregatorStore aggStore;