VSCE: Claim sourcegraph namespace with Eclipse

Created by: abeatrix

Our extension is currently published to the open-vsx registry as an unverified publisher, so anyone can publish extensions to the sourcegraph namespace until it is claimed (link to docs)

We will need to file a ticket with Eclipse to claim the Sourcegraph namespace (how-to-claim-a-namespace). Once we are the owner of the sourcegraph namespace, we can add sourcegraph-bot as one of the owners for administrating and publishing purposes.

Claim submitted here: https://github.com/EclipseFdn/open-vsx.org/issues/1088