Add changelog 0.3 (#123)

* update CHANGELOG-0.3.md
Signed-off-by: neweyes <neweyes1987@gmail.com>

CHANGELOG/CHANGELOG-0.3.md

-- [Release v0.3.0 / 2021-05-20](#release-v030--2021-05-20)
+- [v0.3.0 / 2021-05-20](#v030--2021-05-20)
   - [Features and Enhancements](#features-and-enhancements)
   - [Bug Fixes](#bug-fixes)
   - [Documentation](#documentation)
 
-# Release v0.3.0 / 2021-05-20
+# v0.3.0 / 2021-05-20
 
 ## Features and Enhancements
 
-* edgeadm tool supports to create a new edge Kubernetes cluster([#97](https://github.com/superedge/superedge/pull/97), [@attlee-wang](https://github.com/attlee-wang)), and its [usage](https://github.com/superedge/superedge/blob/main/docs/installation/install_edge_kubernetes.md) is consistent with Kubedm, or create an edge Kubernetes cluster follow by [Quickstart Guide](https://github.com/superedge/superedge/blob/main/README.md).
-* edgeadm tool supports adding new nodes to the edge kubernetes cluster([#87](https://github.com/superedge/superedge/pull/87), [@wenhuwang](https://github.com/wenhuwang)). Before superedge v0.3.0, we can use `edgeadm change` to convert the existing original kubernetes cluster to the edge kubernetes cluster, but we can't add new nodes after change.
-* when the node is offline, it can also sense the state of other nodes and identify whether the back-end pod is reachable, so as to avoid routing traffic to abnormal nodes([#86](https://github.com/superedge/superedge/pull/86), [@chenkaiyue](https://github.com/chenkaiyue))
-* support golang 1.16([#91](https://github.com/superedge/superedge/pull/91), [@SataQiu](https://github.com/SataQiu)).
+* Edgeadm supported creating native Kubernetes cluster with pre-installed SuperEdge components([#97](https://github.com/superedge/superedge/pull/97), [@attlee-wang](https://github.com/attlee-wang)), [Usage](https://github.com/superedge/superedge/blob/main/docs/installation/install_edge_kubernetes.md) or [Quickstart Guide](https://github.com/superedge/superedge/blob/main/README.md).
+* Edgeadm supported adding new nodes to edge Kubernetes cluster([#87](https://github.com/superedge/superedge/pull/87), [@wenhuwang](https://github.com/wenhuwang)).
+* Enhanced edge autonomy by detecting failing nodes within the offline regions, so as to avoid routing traffic to abnormal nodes([#86](https://github.com/superedge/superedge/pull/86), [@chenkaiyue](https://github.com/chenkaiyue))
+* Supported Golang 1.16([#91](https://github.com/superedge/superedge/pull/91), [@SataQiu](https://github.com/SataQiu)).
 
 
 ## Bug Fixes
 
-* Fixed `kubectl cp` connection can not be disconnected after copy file over([#78](https://github.com/superedge/superedge/pull/78), [@00pf00](https://github.com/00pf00)).
+* Fixed a bug that caused kubectl cp failing to disconnect after copying([#78](https://github.com/superedge/superedge/pull/78), [@00pf00](https://github.com/00pf00)).
 
 
 ## Documentation
 
-* update roadmap([roadmap](https://github.com/superedge/superedge/blob/main/docs/roadmap.md), [@ruyingzhe](https://github.com/ruyingzhe))
-* Introduction to use edgeadm to create an edge Kubernetes cluster.
-* Fixed wrrong information in install_manually docs([#73](https://github.com/superedge/superedge/pull/73), [@huweihuang](https://github.com/huweihuang)).
+* Added quickstart guide to create edge Kubernetes cluster using Edgeadm.
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