Include a higher timeout value to avoid timeouts.

Checking out framework can often take longer than the default
(300 seconds). This gives a 10min limit to creating a new project.

composer.json

@@ -13,5 +13,8 @@
 		"silverstripe/buildtools": "*",
 		"phpunit/phpunit": "3.7.*"
 	},
+	"config": {
+		"process-timeout": 600	
+	},
 	"minimum-stability": "dev"
-}
+}