Add pure Python implementation

Add pure Python implementation available at https://github.com/rayokota/jsonata-python

Author: rayokota

docs/overview.md

@@ -29,6 +29,7 @@ The following are known implementations of JSONata in addition to the primary im
 |Java|https://github.com/dashjoin/jsonata-java|Native port of reference|2.0.3|
 |.NET|https://github.com/mikhail-barg/jsonata.net.native|Native implementation|1.8.5|
 |Python|https://github.com/qlyoung/pyjsonata|API bindings based on C bindings|1.8.3|
+|Python|https://github.com/rayokota/jsonata-python|Native port of reference|2.0.5|
 |Rust|https://github.com/johanventer/jsonata-rust|Implementation work in progress| |
 |Rust|https://github.com/Stedi/jsonata-rs|Actively-developed fork of jsonata-rust| |