Fix typo in README.md for custom agents section (#355)

Author: davidortinau

README.md

@@ -58,7 +58,7 @@ To make it easy to add these customizations to your editor, we have created a [M
 
 ### 🤖 Custom Agents
 
-Custom agents can be used in Copilot coding agent (CCA), VS Code, and Copilot CLI (coming soon). For CCA, when assingning an issue to Copilot, select the custom agent from the provided list. In VS Code, you can activate the custom agent in the agents session, alongside built-in agents like Plan and Agent.
+Custom agents can be used in Copilot coding agent (CCA), VS Code, and Copilot CLI (coming soon). For CCA, when assigning an issue to Copilot, select the custom agent from the provided list. In VS Code, you can activate the custom agent in the agents session, alongside built-in agents like Plan and Agent.
 
 ### 🎯 Prompts