Bump pug from 2.0.4 to 3.0.1 in /samples/sample-app

Bumps [pug](https://github.com/pugjs/pug) from 2.0.4 to 3.0.1.
- [Release notes](https://github.com/pugjs/pug/releases)
- [Commits](https://github.com/pugjs/pug/compare/pug@2.0.4...pug@3.0.1)

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

Author: dependabot[bot]

samples/sample-app/package.json

@@ -11,7 +11,7 @@
     "express": "^4.17.1",
     "imagekit": "^3.0.3",
     "open": "^7.0.2",
-    "pug": "^2.0.4",
+    "pug": "^3.0.1",
     "uuid": "^3.4.0"
   }
 }