refactor

change var to const for consitency in file

setup/setup.js

@@ -47,7 +47,7 @@ function checkSymlinkExistsAsync() {
 }
 
 function ensureYarnInstalledAsync() {
-	var semverPattern = /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(-(0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(\.(0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*)?(\+[0-9a-zA-Z-]+(\.[0-9a-zA-Z-]+)*)?$/;
+	const semverPattern = /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(-(0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(\.(0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*)?(\+[0-9a-zA-Z-]+(\.[0-9a-zA-Z-]+)*)?$/;
 	return execGetOutput("yarn", ["-v"], "Check yarn version")
 		.then(stdout => semverPattern.test(stdout), () => false)
 		.then(hasYarn => hasYarn || installYarnAsync());