add release notes

CHANGE.md

 # Release Notes
 ---
+## 1.4.5
+
+### Bugfixes
+- [Fix too many files open error](https://github.com/apache/dubbo-go/pull/828)  [@wenxuwan](https://github.com/wenxuwan) Milestone: [https://github.com/apache/dubbo-go/milestone/6](https://github.com/apache/dubbo-go/milestone/6?closed=1)
 
 ## 1.5.4
 

README.md

@@ -16,6 +16,8 @@ Apache License, Version 2.0
 
 ## Release note ##
 
+[v1.4.5 - Nov 18, 2020](https://github.com/apache/dubbo-go/releases/tag/v1.4.5)
+
 [v1.5.4 - Nov 1, 2020](https://github.com/apache/dubbo-go/releases/tag/v1.5.4)
 
 [v1.5.3 - Sep 23, 2020](https://github.com/apache/dubbo-go/releases/tag/v1.5.3)

README_CN.md

@@ -15,6 +15,8 @@ Apache License, Version 2.0
 
 ## 发布日志 ##
 
+[v1.4.5 - 2020年11月18日](https://github.com/apache/dubbo-go/releases/tag/v1.4.5)
+
 [v1.5.4 - 2020年11月1日](https://github.com/apache/dubbo-go/releases/tag/v1.5.4)
 
 [v1.5.3 - 2020年9月23日](https://github.com/apache/dubbo-go/releases/tag/v1.5.3)