Update CHANGES.md (#39)

* Update CHANGES.md

CHANGES.md

 # Changes
 
+## 0.2.0
+
+1. Adapt the new v3 protocol.
+2. Implement correlation protocol.
+3. Support batch segment report.
+4. Fix wrong context carrier endpoint data.
+5. Rocks: fixed wrong version of luarocks.
+6. Remove first ref variable.
+7. Uniform the SpanLayer type name.
+
 ## 0.1.0
 1. Establish the LUA tracing core.
 2. Add the tracer implementation based on Nginx OpenResty.
+