Merge pull request #501 from cloudfoundry/ameowlia-patch-3

add cloudfoundry/healthchecker to ARP WG

Author: AP-Hunt

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

@@ -317,6 +317,7 @@ areas:
   - cloudfoundry/cf-tcp-router
   - cloudfoundry/envoy-nginx-release
   - cloudfoundry/gorouter
+  - cloudfoundry/healthchecker
   - cloudfoundry/logging-route-service
   - cloudfoundry/multierror
   - cloudfoundry/nats-release