CI: semver-checks generates a lot of GitHub comments

[avelanarius]

In PRs with a lot of activity, such as #925, cargo semver-checks CI can be a bit too verbose with its comments, commenting after every push is made to the PR.

To make it less annoying in such a cases, it could:

• Hide its previous comments.
• Only submit a single comment and in next runs of cargo semver-checks could edit that (single) existing comment. (see Add --edit-last-or-create option or enhance the functionality of --edit-last for PR comments cli/cli#6790 for ways to do it)
• Use "job summaries" feature, however this makes it harder to notice the output of cargo semver-checks.