add pashagolub/pgxmock (#5548)

* add pashagolub/pgxmock

* fix order

README.md

@@ -2504,6 +2504,7 @@ _Libraries for testing codebases and generating test data._
 - [mockhttp](https://github.com/tv42/mockhttp) - Mock object for Go http.ResponseWriter.
 - [mooncake](https://github.com/GuilhermeCaruso/mooncake) - A simple way to generate mocks for multiple purposes.
 - [moq](https://github.com/matryer/moq) - Utility that generates a struct from any interface. The struct can be used in test code as a mock of the interface.
+- [pgxmock](https://github.com/pashagolub/pgxmock) - A mock library implementing [pgx - PostgreSQL Driver and Toolkit](https://github.com/jackc/pgx/).
 - [timex](https://github.com/cabify/timex) - A test-friendly replacement for the native `time` package.
 - [xgo](https://github.com/xhd2015/xgo) - A general pureposed function mocking library.