changelog: describe changes since 0.7.0

This patch add CHANGELOG.md file. Current CHANGELOG contents covers
version 0.7.0, 0.7.1 changes and currently unreleased changes. For
changes in versions before 0.7.0, see releases GitHub page [1].

1. https://github.com/tarantool/tarantool-python/releases

Author: DifferentialOrange

CHANGELOG.md

@@ -0,0 +1,48 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## Unreleased
+
+### Added
+- Reusable testing workflow for integration with tarantool artifacts
+  (PR #192).
+
+### Changed
+- Clarify license of the project (BSD-2-Clause) (PR #210, #197).
+- Migrate CI to GitHub Actions (PR #213, PR #216, #182).
+- Various improvements and fixes in README (PR #210, PR #215).
+
+### Fixed
+- json.dumps compatibility with Python 2 (PR #186). 
+- Unix socket support in mesh_connection (PR #189, #111).
+- Various fixes in tests (PR #189, #111, PR #195, #194).
+
+
+## 0.7.1 - 2020-12-28
+
+### Fixed
+- msgpack library dependency (PR #185).
+
+
+## 0.7.0 - 2020-12-28
+
+Caution: Use tarantool-python 0.7.1 instead of 0.7.0. It fixes
+the dependency on the msgpack library.
+
+### Added
+- Support msgpack 1.0.0 (#155, PR #173).
+- SQL support (<connection>.execute() method) (#159, PR #161).
+- Allow to receive a Tarantool tuple as a Python tuple, not a list, with
+    use_list=False connection option (#166, PR #161).
+- Support the Database API (PEP-0249) (PR #161).
+
+### Changed
+- Various improvements in README (PR #147, PR #151, PR #180).
+
+### Fixed
+- Support encoding=None connections (PR #172).
+- Various improvements and fixes in tests (8ff9a3f, bd37703, PR #165,
+  #178, PR #179, PR #181).