Update jmx-scraper/src/integrationTest/java/io/opentelemetry/contrib/jmxscraper/assertions/AttributeMatcher.java

Co-authored-by: jason plumb <[email protected]>

Author: robsunday

jmx-scraper/src/integrationTest/java/io/opentelemetry/contrib/jmxscraper/assertions/AttributeMatcher.java

@@ -10,6 +10,7 @@
 /** Implements functionality of matching data point attributes. */
 public class AttributeMatcher {
   private final String attributeName;
+  @Nullable
   private final String attributeValue;
 
   /**