feat: add forked version of pgconn

v1.14.4 - Improve cancel request handling for pgbouncer compatibility

- Fix CancelRequest to wait for server acknowledgment
- Improve error handling in cancel request
- Add pgbouncer compatibility testing
- Remove unnecessary type casts in cancel request protocol

Release v5.7.5

Add v5.7.4 to changelog

Update changelog for v5.7.3

Create changelog for v5.7.2

Release v5.7.1

Release v5.7.0

Release v5.6.0

Fix spelling in changelog