chore: update README.md

README.md

@@ -37,7 +37,7 @@ Terraform module to create an ECS Service for a web app (task), and an ALB targe
 >
 > <details>
 > <summary><strong>Watch demo of using Atmos with Terraform</strong></summary>
-> <img src="https://github.com/cloudposse/atmos/blob/master/docs/demo.gif?raw=true"/><br/>
+> <img src="https://github.com/cloudposse/atmos/blob/main/docs/demo.gif?raw=true"/><br/>
 > <i>Example of running <a href="https://atmos.tools"><code>atmos</code></a> to manage infrastructure from our <a href="https://atmos.tools/quick-start/">Quick Start</a> tutorial.</i>
 > </detalis>