update denylist

[kgjenkins]

• added metadata-issues, which is an issue-only repo transferred from geoblacklight/geoblacklight-metadata
• removed metadatarepository, which has been renamed to shared-repository and actually should get harvested for records

[eliotjordan]

@kgjenkins This just needs a small update to the rake task spec: https://github.com/OpenGeoMetadata/GeoCombine/blob/main/spec/lib/tasks/geo_combine_spec.rb#L27

Replace 20 with 21,

[eliotjordan]

I updated the PR to fix the failing spec and added a commit to help with intermittently failing tests of the rake task.

[kgjenkins]

I'm trying to understand that test... is 21 the number of repos it expects to find that are not on the denylist?