【backport】Release v0.6.1 (openyurtio#739)

* bugfix: panic happened when x-tunnel-server-svc service type is lb (openyurtio#724)

* enhancement: tunnel-server supports to proxy requests that access tunnel-server directly with specified destination (openyurtio#725)

* cache-agent for yurthub support '*' (openyurtio#727)

* cache-agent for yurthub support '*'

Signed-off-by: 刘畅 <basefly@outlook.com>

* add unit test for cache_agents of yurthub

Signed-off-by: 刘畅 <basefly@outlook.com>

* fmt code

Signed-off-by: 刘畅 <basefly@outlook.com>

* add NoArgs check for cmds (openyurtio#728)

* fix: not initialized `sets.String` cause panic (openyurtio#733)

Co-authored-by: zhanglifang@chinatelecom.cn <zhanglifang@chinatelecom.cn>

Co-authored-by: hhstu <55697154+hhstu@users.noreply.github.com>
Co-authored-by: Yifei Zhang <chpzhangyifei@qq.com>
Co-authored-by: DrmagicE <379342542@qq.com>
Co-authored-by: zhanglifang@chinatelecom.cn <zhanglifang@chinatelecom.cn>

[docs] revise readme and changelog for OpenYurt v0.6.0 (openyurtio#709)

release v0.5.0

1. add release v0.4.1 info into readme (openyurtio#408)

2. add service update right for yurt-tunnel-server

release v0.4.0

release v0.3.0

v0.4.0: release node-resource-manager (openyurtio#324)