Log more info in workflow runs

When an automation action runs ([example](https://github.com/ConduitIO/conduit/runs/7208272294?check_suite_focus=true)), we see the following in the logs in the "Check for old milestones" step:
```
Found Milestone: [object Object]
```
It would be good to stringify the object before logging it.

In the "Echo the found milestone" step, no milestone ID is logged.

In the "Manage Milestones" step, we log only the issue ID:
```
Issue Deleted From Roadmap: MDU6SXNzdWUxMDk5Mjg0OTM2
```
It would be good to log the issue title too (which makes it possible to perform an ad-hoc sanity check of the run).