add delta flag to asset id if needed

[asplinsol]

This PR fixes an error I was seeing while publishing a release using electron-forge/publisher-eletron-release-server.

The assets being uploaded included both a full and delta nupkg and electron-release-server returned a HTTP error 400 with the error explanation that the asset id already exists.

The fix is to include delta in the generated asset ID so that it is a unique primary key.

[asplinsol]

@ArekSredzki my PR I believe is for the same issue as PR #241 but handled in a much simpler way (in keeping with other parts of the code that check for a delta string in the name).

[lauer]

Thanks for your fix, I was testing the same plugin (publisher-electron-release-server), but it stopped me because if this error. So i still upload using SSH to a server.

@ArekSredzki Could you please review and merge this change?

@asplinsol are you using this release-server in prod somewhere? and on an open-source project where you share the implementation?

[jasplin]

@lauer thanks for the comments, you may want to also look at #302 in case you need it?

At the moment I've put my use of this release-server on hold - I had more errors and ran out of time on the project. Like you I'm still using alternatives.

I might come back to it when I have some time because I really like the customer friendly, flexible UI but until then I will be monitoring for others to contribute :)

[lauer]

@jasplin What errors did you also have? And which solution do you have now?
I was hoping that all the PR's you created combined to make the app stable enough to be used for a small project I have.