Packages: Add pluto-pg

Author: Sainan

docs/Packages.md

@@ -51,3 +51,4 @@ While Pluto's standard library is still growing, a few packages are available to
 - [pluto-query](https://github.com/PlutoLang/pluto-query) — expands Pluto's `xml` library with query selector functionality
 - [pluto-dns](https://github.com/PlutoLang/pluto-dns) — DNS client library
 - [pluto-s3](https://github.com/PlutoLang/pluto-s3) —  S3 client library including AWS4 and HMAC algorithms
+- [pluto-pg](https://github.com/PlutoLang/pluto-pg) —  Postgres wire protocol client library including SASL SCRAM algorithm