* Remove pulumi.io reference in tests
* Remove pulumi.io references in Dockerfiles
* Remove pulumi.io references in CONTRIBUTING.md
* Update README.md's
* Use correct logo
We changed the `pulumi update` command to be `pulumi up` a while back
(`update` is an alias of `up`). This change just makes it so we refer to
the actual command, `pulumi up`, instead of the older `pulumi update`.
This includes a few changes:
* The repo name -- and hence the Go modules -- changes from pulumi-fabric to pulumi.
* The Node.js SDK package changes from @pulumi/pulumi-fabric to just pulumi.
* The CLI is renamed from lumi to pulumi.