Bump shepherd.js from 15.0.0 to 15.2.1

Bumps [shepherd.js](https://github.com/shipshapecode/shepherd) from 15.0.0 to 15.2.1.
- [Release notes](https://github.com/shipshapecode/shepherd/releases)
- [Changelog](https://github.com/shipshapecode/shepherd/blob/main/CHANGELOG.md)
- [Commits](https://github.com/shipshapecode/shepherd/commits)

---
updated-dependencies:
- dependency-name: shepherd.js
  dependency-version: 15.2.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

package.json

@@ -73,7 +73,7 @@
     "recordrtc": "^5.6.2",
     "select2": "^4.1.0-rc.0",
     "select2-to-tree": "https://github.com/clivezhg/select2-to-tree",
-    "shepherd.js": "^15.0.0",
+    "shepherd.js": "^15.2.1",
     "skrollr": "github:Prinzhorn/skrollr",
     "spin.js": "^4.1.2",
     "stackedit-js": "^1.0.7",

yarn.lock

@@ -3451,10 +3451,10 @@ shell-quote@^1.6.1:
   resolved "https://registry.yarnpkg.com/shell-quote/-/shell-quote-1.8.3.tgz#55e40ef33cf5c689902353a3d8cd1a6725f08b4b"
   integrity sha512-ObmnIF4hXNg1BqhnHmgbDETF8dLPCggZWBjkQfhZpbszZnYur5DUljTcCHii5LC3J5E0yeO/1LIMyH+UvHQgyw==
 
-shepherd.js@^15.0.0:
-  version "15.0.0"
-  resolved "https://registry.yarnpkg.com/shepherd.js/-/shepherd.js-15.0.0.tgz#75993e61612673c45097c507960f8ca5b02f8e2f"
-  integrity sha512-iekM8hgheL5ojluJGewnLFtdL2WgAfkTQUPi6Z5X1R7bhc6riMdK2R5LVc6tZjBDyh/GNeDEehrCzE10+N6Wcw==
+shepherd.js@^15.2.1:
+  version "15.2.1"
+  resolved "https://registry.yarnpkg.com/shepherd.js/-/shepherd.js-15.2.1.tgz#5a2dd307209e052f51e42427e0650f4a3b1d5b81"
+  integrity sha512-afzZzj3K7sFfnkuze4TmHT4RuxMzPtpxs4SoXBBOYdJgbVL4dG44E7LEOyk418t1JuBu0Ji3nsYczJbrbv76LQ==
   dependencies:
     "@floating-ui/dom" "^1.7.5"
     deepmerge-ts "^7.1.5"