Bump io.dropwizard.metrics:metrics-core from 4.2.20 to 4.2.21

Bumps [io.dropwizard.metrics:metrics-core](https://github.com/dropwizard/metrics) from 4.2.20 to 4.2.21.
- [Release notes](https://github.com/dropwizard/metrics/releases)
- [Commits](dropwizard/metrics@v4.2.20...v4.2.21)

---
updated-dependencies:
- dependency-name: io.dropwizard.metrics:metrics-core
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -56,7 +56,7 @@
 
     <spotless.check.skip>true</spotless.check.skip>
     <slf4j.version>1.7.36</slf4j.version>
-    <metrics.version>4.2.20</metrics.version>
+    <metrics.version>4.2.21</metrics.version>
     <micrometer.version>1.11.5</micrometer.version>
     <micrometer-tracing.version>1.1.4</micrometer-tracing.version>
     <opentelemetry.version>1.31.0</opentelemetry.version>