docs: Add more teams (#461)

docs/src/getting-started/projects.md

@@ -5,3 +5,5 @@ Projects using Anchor include
 * [Serum](https://github.com/project-serum)
 * [Synthetify](https://github.com/Synthetify)
 * [SolFarm](https://solfarm.io/)
+* [Zeta Markets](https://zeta.markets/)
+* [Saber](https://saber.so)