Pgdoc-datatype-parser

New PostgreSQL supported versions

- v13.3
- v12.7
- v11.12
- v10.17
- v9.6.22

- Raise 'FileNotFoundError' when custom release file is not found.
- Raise 'InvalidReleaseVersion' is version is not supported.
- Allow redirection from 'X.Y.0' versions to 'X.Y' if shorter version doesn't exists.

New PostgreSQL supported versions

- v13.2
- v12.6
- v11.11
- v10.16
- v9.6.21
- v9.5.25

- Fix metadata error in setup.

README updated

- Switch CI to Github Actions.