Bump js-yaml from 4.1.1 to 5.4.1 in /theme

Bumps [js-yaml](https://github.com/nodeca/js-yaml) from 4.1.1 to 5.4.1.
- [Changelog](https://github.com/nodeca/js-yaml/blob/master/CHANGELOG.md)
- [Commits](nodeca/js-yaml@4.1.1...5.4.1)

---
updated-dependencies:
- dependency-name: js-yaml
  dependency-version: 5.4.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

theme/package.json

@@ -58,7 +58,7 @@
   "dependencies": {
     "@fortawesome/fontawesome-free": "^7.0.1",
     "js-cookie": "^3.0",
-    "js-yaml": "^4.1",
+    "js-yaml": "^5.4",
     "tippy.js": "^6.3"
   }
 }

theme/yarn.lock

@@ -2423,13 +2423,20 @@ js-tokens@^4.0.0:
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-4.0.0.tgz#19203fb59991df98e3a287050d4647cdeaf32499"
   integrity sha512-RdJUflcE3cUzKiMqQgsCu06FPu9UdIJO0beYbPhHN4k6apgJtifcoCtT9bcxOpYBtpD2kCM6Sbzg4CausW/PKQ==
 
-js-yaml@^4.1, js-yaml@^4.1.0:
+js-yaml@^4.1.0:
   version "4.1.1"
   resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-4.1.1.tgz#854c292467705b699476e1a2decc0c8a3458806b"
   integrity sha512-qQKT4zQxXl8lLwBtHMWwaTcGfFOZviOJet3Oy/xmGk2gZH677CJM9EvtfdSkgWcATZhj/55JZ0rmy3myCT5lsA==
   dependencies:
     argparse "^2.0.1"
 
+js-yaml@^5.4:
+  version "5.4.1"
+  resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-5.4.1.tgz#4629d91d4b4551f300435f0e4127899710f816fb"
+  integrity sha512-28R/k+NAjeuf7+CKlTxWZVExJGwVVLwY06DgEnOMz2gEpfNkDcD7QvyiVPT0xy0XXhU8vHsd4Ot42OOPdJG7dQ==
+  dependencies:
+    argparse "^2.0.1"
+
 jsesc@^3.0.2, jsesc@~3.1.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/jsesc/-/jsesc-3.1.0.tgz#74d335a234f67ed19907fdadfac7ccf9d409825d"