modify readme

README.md

@@ -18,5 +18,22 @@ We recommend using __helm-chart__ as your first choice.
 
 ### helm-chart 
 
-This is recommended as the best practice to deploy SkyWalking backend stack into kubernetes cluster. You can pick a 
- sub folder base on version your desired version.
+This is recommended as the best practice to deploy SkyWalking backend stack into kubernetes cluster. 
+
+#### old chart position table
+
+| SkyWalking version | Chart position                                               |
+| ------------------ | ------------------------------------------------------------ |
+| 6.0.0-GA           | [6.0.0-GA](https://github.com/apache/skywalking-kubernetes/tree/legacy-helm-chart/helm-chart/helm2/6.0.0-GA) |
+| 6.1.0              | [6.1.0](https://github.com/apache/skywalking-kubernetes/tree/legacy-helm-chart/helm-chart/helm2/6.1.0) |
+| 6.3.0              | [6.3.0](https://github.com/apache/skywalking-kubernetes/tree/legacy-helm-chart/helm-chart/helm3/6.3.0) |
+| 6.4.0              | [6.4.0](https://github.com/apache/skywalking-kubernetes/tree/legacy-helm-chart/helm-chart/helm3/6.4.0) |
+
+Note:  The source code for old charts are in the **legacy-helm-chart** branch.
+
+#### release chart table 
+| SkyWalking version | Chart version |
+| ------------------ | ------------- |
+| 6.5.0              | 1.0.0         |
+
+Note:  The source code for the release chart is located in the chart folder in the master branch.
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