fix: git add files in dependabot workflow

[salasberryfin]

What this PR does / why we need it:

Dependabot CI checks are failing on some PRs after replacing the no longer supported action with manual steps example. Looks like this is because the Action we were using sets a default git add . here and it is missing now, so the commit returns error code 1 when there are no changes to commit. This PR simply adds a git add . which hopefully is enough to mimic the removed action's behavior.

Which issue(s) this PR fixes: Fixes #

Special notes for your reviewer:

Checklist:

• [x] squashed commits into logical changes
• [ ] includes documentation
• [ ] adds unit tests
• [ ] adds or updates e2e tests

[Danil-Grigorev]

We might want to explore using rancher/renovate bot to do these operation in the future. Current workflow is unfortunately very limited and requires manual patches within the changing requirements

[salasberryfin]

Thanks @Danil-Grigorev, I agree with your point. I guess we can keep this as a temporary solution and think about migrating this to a more sophisticated alternative.

[Danil-Grigorev]

Yeah, same thinking @salasberryfin. Opened an issue for the future: https://github.com/rancher/turtles/issues/558