Bump elastic-apm from 6.13.2 to 6.15.0

Bumps [elastic-apm](https://github.com/elastic/apm-agent-python) from 6.13.2 to 6.15.0.
- [Release notes](https://github.com/elastic/apm-agent-python/releases)
- [Changelog](https://github.com/elastic/apm-agent-python/blob/main/CHANGELOG.asciidoc)
- [Commits](elastic/apm-agent-python@v6.13.2...v6.15.0)

---
updated-dependencies:
- dependency-name: elastic-apm
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

setup.py

@@ -26,7 +26,7 @@
     ],
     extras_require={
         "lock-redis": ["redis==4.5.1"],
-        "metrics-elasticsearch": ["elastic-apm==6.13.2"],
+        "metrics-elasticsearch": ["elastic-apm==6.15.0"],
     },
     setup_requires=["black==22.10.0"],
 )