package.json: update the dependencies

Add a dependency on slash for development purposes.

Author: compnerd

package.json

@@ -36,7 +36,8 @@
 		"eslint-plugin-jsdoc": "^33.0.0",
 		"fs-extra": "^9.1.0",
 		"jest": "^26.6.3",
-		"prettier": "^2.2.1"
+		"prettier": "^2.2.1",
+		"slash": "^4.0.0"
 	},
 	"eslintConfig": {
 		"root": true,