Remove unnecessary `path.sep` usage

src/index.js

@@ -6,7 +6,7 @@ const defaultValue = require("default-value");
 
 let defaultCheckers = {
 	"package.json": function(directory) {
-		let parentPackageFile = path.join(directory, `..${path.sep}..${path.sep}package.json`);
+		let parentPackageFile = path.join(directory, "..", "..", "package.json");
 
 		try {
 			fs.accessSync(parentPackageFile);
@@ -74,7 +74,7 @@ module.exports = function(options) {
 		}
 
 		if (rootFound === false) {
-			currentPath = path.join(currentPath, `..${path.sep}..`);
+			currentPath = path.join(currentPath, "..", "..");
 		}
 	}