chore: bump version to 1.28.0

Author: krutilov

package.json

@@ -1,6 +1,6 @@
 {
   "name": "kotlin-playground",
-  "version": "1.28.0-alpha.4",
+  "version": "1.28.0",
   "description": "Self-contained component to embed in websites for running Kotlin code",
   "keywords": [
     "kotlin",
@@ -50,7 +50,6 @@
     "style-loader": "^0.23.1",
     "svg-fill-loader": "0.0.8",
     "svg-url-loader": "^2.3.2",
-    "terser-webpack-plugin": "^4.2.3",
     "url-search-params": "1.1.0",
     "webpack": "^4.31.0",
     "webpack-cli": "^3.3.2",