- updates agenda workflow so it closes older agenda issues automatically

[baywet]

related #3420

[lornajane]

How long will it leave the issues open for? I would suggest something over 2 weeks, so we can always look at the previous meeting notes, even if we skip a meeting one week.

[baywet]

@lornajane right now it closes the issue as soon as the date in the title is passed, but runs only every week, so that should give us a week effectively.
We could introduce a delay if the TDC decides it.

[baywet]

Notes from the meeting:

• wait 10 days before close the issue.
• look into unpinning the issue as we close them.

[baywet]

@lornajane @darrelmiller @MikeRalphson @webron :

• added the delay of 10 days before closing the agenda item
• added pinning/unpinning the issues

I think this is ready to merge.