Bump rollup-plugin-handlebars-plus from 0.2.5 to 0.4.2 in /assets

Bumps [rollup-plugin-handlebars-plus](https://github.com/mixmaxhq/rollup-plugin-handlebars-plus) from 0.2.5 to 0.4.2.
- [Release notes](https://github.com/mixmaxhq/rollup-plugin-handlebars-plus/releases)
- [Changelog](https://github.com/mixmaxhq/rollup-plugin-handlebars-plus/blob/master/CHANGELOG.md)
- [Commits](mixmaxhq/rollup-plugin-handlebars-plus@v0.2.5...v0.4.2)

---
updated-dependencies:
- dependency-name: rollup-plugin-handlebars-plus
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

assets/package-lock.json

@@ -76,7 +76,7 @@
     "postcss-csso": "^5.0.1",
     "postcss-flexbugs-fixes": "^5.0.2",
     "rollup": "^2.61.1",
-    "rollup-plugin-handlebars-plus": "0.2.5",
+    "rollup-plugin-handlebars-plus": "0.4.2",
     "rollup-plugin-istanbul": "^3.0.0",
     "rollup-plugin-terser": "^7.0.2",
     "rollup-plugin-vue": "5.1.9",