Propose reviewers for Logging and Metrics

Both Jovan and Felix were active in the Logging and Metrics community.

Jovan posted 106 messages in the logging-and-metrics slack channel, amongst many other topics about exhaustive loggregator load tests, and contributed several PRs (https://github.com/search?q=org%3Acloudfoundry+chombium&type=issues).

Felix is also active on slack and is the main contributor to the mTLS for syslog drain feature cloudfoundry/loggregator-agent-release#119

Author: stefanlay

toc/working-groups/app-runtime-platform.md

@@ -227,6 +227,11 @@ areas:
     github: ctlong
   - name: Matthew Kocher
     github: mkocher
+  reviewers:
+  - name: Jovan Kostovski
+    github: chombium
+  - name: Felix Hambrecht
+    github: fhambrec
   repositories:
   - cloudfoundry/bosh-system-metrics-forwarder-release
   - cloudfoundry/cf-drain-cli