changelog: consistency with doc

Closes #67

Author: DifferentialOrange

CHANGELOG.md

@@ -15,7 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   type. `tarantool.Datetime` may be encoded to Tarantool datetime
   objects.
 
-  You can create `tarantool.Datetime` objects either from msgpack
+  You can create `tarantool.Datetime` objects either from MsgPack
   data or by using the same API as in Tarantool:
 
   ```python
@@ -73,7 +73,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   type. `tarantool.Interval` may be encoded to Tarantool interval
   objects.
 
-  You can create `tarantool.Interval` objects either from msgpack
+  You can create `tarantool.Interval` objects either from MsgPack
   data or by using the same API as in Tarantool:
 
   ```python