Add regression test to alpine / master ; add 13-3.0 debian + alpine

[ImreSamu]

This PR

• [x] add minimal regress test to postgis -alpine and -master
• [x] add 13-3.0 debian + alpine ( fix https://github.com/postgis/docker-postgis/issues/195 )
  • https://www.postgresql.org/message-id/E1jvL7B-0007Se-71%40atalia.postgresql.org
• [x] testing ...

[ImreSamu]

status: testing & waiting for https://github.com/postgis/docker-postgis/pull/204

[phillipross]

Looks good so far and all my local testing is fine. Is there anything more to be done?

[ImreSamu]

@phillipross : Let's go ... you can merge ... :+1: