Bump rollup-plugin-license from 3.3.1 to 3.4.0 (#2851)

Bumps [rollup-plugin-license](https://github.com/mjeanroy/rollup-plugin-license) from 3.3.1 to 3.4.0.
- [Changelog](https://github.com/mjeanroy/rollup-plugin-license/blob/master/CHANGELOG.md)
- [Commits](mjeanroy/rollup-plugin-license@v3.3.1...v3.4.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

shepherd.js/package.json

@@ -90,7 +90,7 @@
     "rollup-plugin-analyzer": "^4.0.0",
     "rollup-plugin-copy": "^3.5.0",
     "rollup-plugin-filesize": "^10.0.0",
-    "rollup-plugin-license": "^3.3.1",
+    "rollup-plugin-license": "^3.4.0",
     "rollup-plugin-livereload": "^2.0.5",
     "rollup-plugin-postcss": "^4.0.2",
     "rollup-plugin-serve": "^2.0.2",