Update README to document health check_port for tcp_router
Update README to document health check_port for tcp_router

[#106809120]

Signed-off-by: Mike Smykowski <88fdbc182ab0267bbdc37542c0ad1dbb9d9ce14e@gmail.com>

cloudfoundry-incubator/cf-routing-release,cloudfoundry-incubator/cf-routing-release,cloudfoundry-incubator/cf-routing-release