Publish Firebird 3.0.13, 4.0.6 and 5.0.3 releases as Docker image

[mrotteveel]

Firebird 3.0.13, Firebird 4.0.6 and Firebird 5.0.3 were released last Tuesday. The Docker images need to be published as well.

[mrotteveel]

I'll prepare a PR

[mrotteveel]

PR: #33

[fdcastel]

Merged! Thanks again, @mrotteveel!