Update JS dependencies (#10450)

Fomantic's update process did fail to update via 'npm install' because
of our config initially but it did work after manually bumping the
version in semantic.json.

Fomantic changes:

https://github.com/fomantic/Fomantic-UI/blob/master/CHANGELOG.md#284

package.json

@@ -7,7 +7,7 @@
   "dependencies": {
     "@primer/octicons": "9.4.0",
     "clipboard": "2.0.4",
-    "fomantic-ui": "2.8.3",
+    "fomantic-ui": "2.8.4",
     "highlight.js": "9.18.1",
     "jquery": "3.4.1",
     "jquery-migrate": "3.1.0",
@@ -30,24 +30,24 @@
     "eslint": "6.8.0",
     "eslint-config-airbnb-base": "14.0.0",
     "eslint-plugin-import": "2.20.1",
-    "fast-glob": "3.1.1",
+    "fast-glob": "3.2.2",
     "less-loader": "5.0.0",
     "mini-css-extract-plugin": "0.9.0",
     "optimize-css-assets-webpack-plugin": "5.0.3",
     "postcss-loader": "3.0.0",
     "postcss-preset-env": "6.7.0",
-    "postcss-safe-parser": "4.0.1",
-    "stylelint": "13.0.0",
-    "stylelint-config-standard": "19.0.0",
+    "postcss-safe-parser": "4.0.2",
+    "stylelint": "13.2.0",
+    "stylelint-config-standard": "20.0.0",
     "svg-sprite-loader": "4.2.1",
     "svgo": "1.3.2",
     "svgo-loader": "2.2.1",
-    "terser-webpack-plugin": "2.3.4",
+    "terser-webpack-plugin": "2.3.5",
     "updates": "9.3.3",
-    "vue-loader": "15.8.3",
+    "vue-loader": "15.9.0",
     "vue-template-compiler": "2.6.11",
-    "webpack": "4.41.5",
-    "webpack-cli": "3.3.10",
+    "webpack": "4.41.6",
+    "webpack-cli": "3.3.11",
     "webpack-fix-style-only-entries": "0.4.0"
   },
   "browserslist": [

semantic.json

@@ -1,5 +1,5 @@
 {
-  "version": "2.8.3",
+  "version": "2.8.4",
   "base": "node_modules/fomantic-ui",
   "paths": {
     "source": {