[FIX] Revert "Switch to maintained fork of "css" package" (#261)

This reverts commit 0abe66a.

The change introduced unexpected regressions due to a bug in `@adobe/css-tools`, see adobe/css-tools#77.

Author: matz3

lib/index.js

@@ -1,7 +1,7 @@
 "use strict";
 
 const path = require("path");
-const css = require("@adobe/css-tools");
+const css = require("css");
 
 
 const diff = require("./diff");

package-lock.json

@@ -82,8 +82,8 @@
 		"url": "git@github.com:SAP/less-openui5.git"
 	},
 	"dependencies": {
-		"@adobe/css-tools": "^4.0.1",
 		"clone": "^2.1.2",
+		"css": "^3.0.0",
 		"mime": "^1.6.0"
 	},
 	"devDependencies": {

package.json

@@ -2,7 +2,7 @@
 "use strict";
 
 const assert = require("assert");
-const css = require("@adobe/css-tools");
+const css = require("css");
 const fs = require("fs");
 const path = require("path");