Don't run image building in PR's branches

[yelizariev]

In private repositories pull requests should not be forked. That is a developer creates a temporary branch for this. Such a branch doesn't need own docker images. So, we need to disable the workflow for such cases.

On the other hand, there is a case when new temporary branch is created to send PRs there. In that case we need the docker images.

So, the specification could be as following:

make images only for main branches (10.0, 11.0, etc.) and development branches (10.0-dev-<some-name>, 11.0-dev-<another-name>