release procedures: automatise updating of GitHub release titles

[tiborsimko]

The release process has become recently more automatised by means of using the conventional commits and the Release Please.

There are some remaining tasks that are being done manually still, such as updating the GitHub release titles.

We could automatise this, so that the release titles would be amended right after the Release Please does its job, for example already from the release pipeline by means of using gh, or else we could add this functionality into reana-dev for example and call it locally.