Bring sass and gulp deps up-to-date

package.json

@@ -16,14 +16,15 @@
     "@fortawesome/fontawesome-free": "^5.15.4",
     "bootstrap-sass": "^3.4.1",
     "gulp": "^4.0.2",
-    "gulp-autoprefixer": "^7.0.1",
+    "gulp-autoprefixer": "^8.0.0",
     "gulp-concat": "^2.6.1",
     "gulp-cssnano": "^2.1.3",
     "gulp-ejs": "^5.1.0",
-    "gulp-sass": "^4.1.0",
+    "gulp-sass": "^5.0.0",
     "gulp-serve": "^1.4.0",
     "gulp-sourcemaps": "^3.0.0",
     "monaco-editor": "^0.23.0",
+    "node-sass": "^6.0.1",
     "rimraf": "^3.0.2",
     "xterm": "^4.14.0",
     "xterm-addon-attach": "^0.6.0",