ci: Group dependabot dependencies updates

[theofidry]

IMO most project do not really benefit from having x10 granular PRs for automated dependencies updates. With this change, dependabot will submit one grouped PR every week. If there is a problematic update, then we can create a dedicate PR to update the offending dependency (as it likely requires manual action anyway) and the rest can still be udpated automatically in one go.

[sgb-io]

@theofidry Agreed re: granular PRs.
Do you know if we can treat the swc_ dependencies differently? Those are very likely to cause breakages, but other deps should be fine

[theofidry]

We can prob. use groups for that https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/customizing-dependency-updates#example-2