Release 1.7.4 (linkerd#2397)

* Release 1.7.4


Signed-off-by: Charles Pretzer <charles@buoyant.io>

Changes for 1.7.3 release (linkerd#2392)

Signed-off-by: Charles Pretzer <charles@buoyant.io>

trigger build

Signed-off-by: Charles Pretzer <charles@buoyant.io>

Release notes for 1.7.1 (linkerd#2367)

Signed-off-by: Charles Pretzer <charles@buoyant.io>

Release notes for 1.7.0 (linkerd#2321)

* Release notes for 1.7.0

Signed-off-by: Zahari Dichev <zaharidichev@gmail.com>

Release Linkerd 1.6.4

Advance headVersion to 1.6.2.2

Signed-off-by: Charles Pretzer <charles@buoyant.io>

Linkerd 1.6.3 (linkerd#2274)

Signed-off-by: Dennis Adjei-Baah <dennis@buoyant.io>

Fix typo

Signed-off-by: Alex Leong <alex@buoyant.io>

Linkerd 1.6.2 release (linkerd#2246)

This Linkerd release includes bug fixes for Namerd's k8s watch API as well as memory management
improvements in the `io.l5d.zk` storage plugin. This release features a new failure detector
module in the `io.l5d.mesh` interpreter that sends "heartbeat" pings on all HTTP/2 connections to
Namerd. This is intended to monitor the health of connections between Linkerd and Namerd so that
connections are torn down and re-established if a ping message is not received within a configured
amount of time.

This release also includes doc updates from the following contributors:
* [LongKB](https://github.com/longkb)
* [Nguyen Phuong An](https://github.com/annp1987)
* [JoeWrightss](https://github.com/JoeWrightss)
* [tuanvcw](https://github.com/tuanvcw)
* [Nguyen Hai Truong](https://github.com/truongnh1992)

A big shoutout to all contributors listed above for their great work!

Full release notes:

* OpenJ9
  * Fixes an issue in Linkerd's OpenJ9 docker image where Linkerd may sometimes run into an
  `OutOfMemoryErrorException` caused by OpenJ9's JDK base image
* Namerd
  * Fixes a memory leak in the `io.l5d.zk` dtab storage module
  * Fixes an issue where Namerd stops watching dtabs if it receives HTTP 404 from a Kubernetes
  API server while restarting a watch API request
* Linkerd Mesh Interpreter
  * Adds a failure detector in the `io.l5d.mesh` interpreter to help monitor the health of
  connections to Namerd. The failure detector can be configured by providing a `minPeriodMs`
  which sets the duration between each successive ping and a `closeTimeoutMs` parameter that
  sets a duration that must elapse before a connection is marked as "unhealthy"
* Adds support for configuring `socketOptions` in the client section of a Linkerd config

Signed-off-by: Dennis Adjei-Baah <dennis@buoyant.io>