Bump the npm_and_yarn group across 1 directory with 5 updates

Bumps the npm_and_yarn group with 5 updates in the / directory:

| Package | From | To |
| --- | --- | --- |
| [ejs](https://github.com/mde/ejs) | `2.7.4` | `3.1.10` |
| [firebase-tools](https://github.com/firebase/firebase-tools) | `3.19.3` | `13.8.0` |
| [highlight.js](https://github.com/highlightjs/highlight.js) | `9.18.5` | `11.9.0` |
| [postcss](https://github.com/postcss/postcss) | `5.2.18` | `8.4.38` |
| [webpack-dev-middleware](https://github.com/webpack/webpack-dev-middleware) | `1.12.2` | `7.2.1` |



Updates `ejs` from 2.7.4 to 3.1.10
- [Release notes](https://github.com/mde/ejs/releases)
- [Commits](mde/ejs@v2.7.4...v3.1.10)

Updates `firebase-tools` from 3.19.3 to 13.8.0
- [Release notes](https://github.com/firebase/firebase-tools/releases)
- [Changelog](https://github.com/firebase/firebase-tools/blob/master/CHANGELOG.md)
- [Commits](firebase/firebase-tools@v3.19.3...v13.8.0)

Updates `highlight.js` from 9.18.5 to 11.9.0
- [Release notes](https://github.com/highlightjs/highlight.js/releases)
- [Changelog](https://github.com/highlightjs/highlight.js/blob/main/CHANGES.md)
- [Commits](highlightjs/highlight.js@9.18.5...11.9.0)

Updates `postcss` from 5.2.18 to 8.4.38
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/commits/8.4.38)

Updates `webpack-dev-middleware` from 1.12.2 to 7.2.1
- [Release notes](https://github.com/webpack/webpack-dev-middleware/releases)
- [Changelog](https://github.com/webpack/webpack-dev-middleware/blob/master/CHANGELOG.md)
- [Commits](webpack/webpack-dev-middleware@v1.12.2...v7.2.1)

---
updated-dependencies:
- dependency-name: ejs
  dependency-type: direct:development
  dependency-group: npm_and_yarn
- dependency-name: firebase-tools
  dependency-type: direct:development
  dependency-group: npm_and_yarn
- dependency-name: highlight.js
  dependency-type: direct:development
  dependency-group: npm_and_yarn
- dependency-name: postcss
  dependency-type: direct:development
  dependency-group: npm_and_yarn
- dependency-name: webpack-dev-middleware
  dependency-type: direct:development
  dependency-group: npm_and_yarn
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -71,24 +71,24 @@
     "css-loader": "^0.23.1",
     "del": "^2.2.1",
     "dotenv-webpack": "^1.3.1",
-    "ejs": "^2.4.2",
+    "ejs": "^3.1.10",
     "eslint": "^3.0.0",
     "eslint-config-airbnb": "^9.0.1",
     "eslint-plugin-import": "^1.10.2",
     "eslint-plugin-jsx-a11y": "^1.5.3",
     "eslint-plugin-react": "^5.2.2",
     "extend": "^3.0.0",
     "file-loader": "^0.9.0",
-    "firebase-tools": "^3.0.4",
+    "firebase-tools": "^13.8.0",
     "front-matter": "^2.1.0",
-    "highlight.js": "^9.5.0",
+    "highlight.js": "^11.9.0",
     "json-loader": "^0.5.4",
     "markdown-it": "^7.0.0",
     "mocha": "^2.5.3",
     "path-to-regexp": "^1.5.3",
     "pixrem": "^3.0.1",
     "pleeease-filters": "^3.0.0",
-    "postcss": "^5.0.21",
+    "postcss": "^8.4.38",
     "postcss-calc": "^5.2.1",
     "postcss-color-function": "^2.0.1",
     "postcss-custom-media": "^5.0.1",
@@ -107,7 +107,7 @@
     "stylelint-config-standard": "^10.0.0",
     "url-loader": "^0.5.7",
     "webpack": "^1.13.1",
-    "webpack-dev-middleware": "^1.6.1",
+    "webpack-dev-middleware": "^7.2.1",
     "webpack-hot-middleware": "^2.12.0"
   },
   "babel": {