Bump js-yaml from 3.14.1 to 4.1.1 in /webpack

Bumps [js-yaml](https://github.com/nodeca/js-yaml) from 3.14.1 to 4.1.1.
- [Changelog](https://github.com/nodeca/js-yaml/blob/master/CHANGELOG.md)
- [Commits](nodeca/js-yaml@3.14.1...4.1.1)

---
updated-dependencies:
- dependency-name: js-yaml
  dependency-version: 4.1.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

webpack/package-lock.json

@@ -1,7 +1,7 @@
 {
   "dependencies": {
     "@octokit/rest": "^21.1.1",
-    "js-yaml": "^3.14.1"
+    "js-yaml": "^4.1.1"
   },
   "devDependencies": {
     "source-map-loader": "^5.0.0",