use an atomic reference for the metrics

Author: atoulme

ibm-mq-metrics/config.yml

@@ -214,4 +214,4 @@ sslConnection:
 
 # Configure the OTLP exporter using system properties keys following the specification https://opentelemetry.io/docs/languages/java/configuration/
 otlpExporter:
-  otel.exporter.otlp.endpoint: http://localhost:4318
+  otel.exporter.otlp.endpoint: http://localhost:4318

ibm-mq-metrics/docs/metrics.md

@@ -834,3 +834,5 @@
 |---|---|---|---|---|---|
 | `error.code` | string | The reason code associated with an error | `2038`; `2543`; `2009` | `Required` | ![Development](https://img.shields.io/badge/-development-blue) |
 | `ibm.mq.queue.manager` | string | The name of the IBM queue manager | `MQ1` | `Required` | ![Development](https://img.shields.io/badge/-development-blue) |
+
+