lock parcel version to 1.21.3

package.json

@@ -22,8 +22,8 @@
   },
   "devDependencies": {
     "gh-pages": "^3.1.0",
-    "parcel-bundler": "^1.12.4",
-    "posthtml-include": "^1.4.3",
-    "sass": "^1.26.9"
+    "parcel-bundler": "1.12.3",
+    "posthtml-include": "^1.6.2",
+    "sass": "^1.32.8"
   }
 }