Fix metric export interval to match spec (#2641)

Author: svetlanabrennan

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/CHANGELOG.md

@@ -6,6 +6,10 @@
   `FormatException` if it fails to parse any of the supported environment
   variables.
 
+* Changed `OtlpExporterOptions.MetricExportIntervalMilliseconds` to default
+  60000 milliseconds.
+  ([#2641](https://github.com/open-telemetry/opentelemetry-dotnet/pull/2641))
+
 ## 1.2.0-beta1
 
 Released 2021-Oct-08

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpExporterOptions.cs

@@ -109,9 +109,9 @@ public OtlpExporterOptions()
         public BatchExportProcessorOptions<Activity> BatchExportProcessorOptions { get; set; } = new BatchExportActivityProcessorOptions();
 
         /// <summary>
-        /// Gets or sets the metric export interval in milliseconds. The default value is 1000 milliseconds.
+        /// Gets or sets the metric export interval in milliseconds. The default value is 60000.
         /// </summary>
-        public int MetricExportIntervalMilliseconds { get; set; } = 1000;
+        public int MetricExportIntervalMilliseconds { get; set; } = 60000;
 
         /// <summary>
         /// Gets or sets the AggregationTemporality used for Histogram