Replace "actions/upload-release-asset" with "softprops/action-gh-release" in draft-release.yml

[seisman]

The actions/upload-release-asset action used in the draft-release.yml workflow is no longer maintained, and softprops/action-gh-release is recommended.

We need to replace the old action with the recommended one.

[maxrjones]

Does this need to happen before rc1? Do you to fix this issue? If you want, I can try submitting an update for the draft-release action.

[seisman]

Does this need to happen before rc1?

It's not necessary, but the rc1 release is a good opportunity to test the new action.

Feel free to work on it before or after rc1.

[maxrjones]

I think there will be an rc2, so we can test a solution then.

[maxrjones]

Just an update that I am going to wait a bit before addressing this issue, in case a decision is made regarding this issue (GenericMappingTools/gmtserver-admin#83) first, which could impact the workflow.