docs: Update projects and add SolFarm (#448)

docs/src/getting-started/projects.md

@@ -4,3 +4,4 @@ Projects using Anchor include
 
 * [Serum](https://github.com/project-serum)
 * [Synthetify](https://github.com/Synthetify)
+* [SolFarm](https://solfarm.io/)