gluon-web-model: uglify flag --support-ie8 is now --ie

From uglify 3.14.0 on, this command is called --ie:

https://github.com/mishoo/UglifyJS/commit/ef5f7fc25e93833396540cf7479685b241bd1b8f

package/gluon-web-model/javascript/gluon-web-model.js

@@ -13,7 +13,7 @@
 /*
 	Build using:
 
-	uglifyjs javascript/gluon-web-model.js -o javascript/gluon-web-model.min.js -c -m --support-ie8
+	uglifyjs javascript/gluon-web-model.js -o javascript/gluon-web-model.min.js -c -m --ie
 */