[Doc] Add release note (#59)

Add release note template and init the first release note content

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>
Co-authored-by: Yikun Jiang <yikunkero@gmail.com>

docs/source/user_guide/release.template.md

@@ -0,0 +1,13 @@
+## {version}
+### Highlights
+- {feature}
+### Bug fixes
+- {bug}
+### Other changes
+- {change}
+### Known issues
+- {issue}
+### Upgrade Notes
+- {upgrade}
+### Deprecation Notes
+- {deprecation}