Update VS Code Extension

This commit replaces the old Ruby VS Code extension into the new Shopify's Ruby LSP as the modern VS Code language support extension.

.devcontainer/devcontainer.json

@@ -20,7 +20,7 @@
 		"vscode": {
 			// Add the IDs of extensions you want installed when the container is created.
 			"extensions": [
-				"rebornix.Ruby"
+				"shopify.ruby-lsp"
 			]
 		}
 	},