initalize artifact client as default export

src/artifact.ts

@@ -1,12 +1,8 @@
-import {ArtifactClient, Client} from './internal/client'
+import {ArtifactClient, DefaultArtifactClient} from './internal/client'
 
-/**
- * Exported functionality that we want to expose for any users of @actions/artifact
- */
 export * from './internal/shared/interfaces'
 export * from './internal/shared/errors'
-export {ArtifactClient}
+export * from './internal/client'
 
-export function create(): ArtifactClient {
-  return Client.create()
-}
+const client: ArtifactClient = new DefaultArtifactClient()
+export default client