doc: add Conduit (#2230)

We recently added a CLI to a our Conduit project, and we use Cobra to power it.

Here's a blog post mentioning it https://meroxa.com/blog/introducing-the-new-conduit-cli:-a-powerful-tool-for-managing-your-pipelines/

Author: raulb

site/content/projects_using_cobra.md

@@ -8,6 +8,7 @@
 - [Cilium](https://cilium.io/)
 - [CloudQuery](https://github.com/cloudquery/cloudquery)
 - [CockroachDB](https://www.cockroachlabs.com/)
+- [Conduit](https://github.com/conduitio/conduit)
 - [Constellation](https://github.com/edgelesssys/constellation)
 - [Cosmos SDK](https://github.com/cosmos/cosmos-sdk)
 - [Datree](https://github.com/datreeio/datree)