Bump io.prometheus:prometheus-metrics-core from 1.3.8 to 1.3.9 (#351)

Bumps io.prometheus:prometheus-metrics-core from 1.3.8 to 1.3.9.

---
updated-dependencies:
- dependency-name: io.prometheus:prometheus-metrics-core
  dependency-version: 1.3.9
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]