fix(deps): update dependency backbone to v1.6.0 (#390)

[![Mend
Renovate](https://app.renovatebot.com/images/banner.svg)](https://renovatebot.com)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [backbone](https://togithub.com/jashkenas/backbone) | [`1.5.0` ->
`1.6.0`](https://renovatebot.com/diffs/npm/backbone/1.5.0/1.6.0) |
[![age](https://developer.mend.io/api/mc/badges/age/npm/backbone/1.6.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![adoption](https://developer.mend.io/api/mc/badges/adoption/npm/backbone/1.6.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![passing](https://developer.mend.io/api/mc/badges/compatibility/npm/backbone/1.5.0/1.6.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/backbone/1.5.0/1.6.0?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

---

### Release Notes

<details>
<summary>jashkenas/backbone (backbone)</summary>

###
[`v1.6.0`](https://togithub.com/jashkenas/backbone/compare/1.5.0...1.6.0)

[Compare
Source](https://togithub.com/jashkenas/backbone/compare/1.5.0...1.6.0)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - "before 4am on Monday" in timezone
America/New_York, Automerge - At any time (no schedule defined).

🚦 **Automerge**: Enabled.

♻ **Rebasing**: Whenever PR is behind base branch, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR has been generated by [Mend
Renovate](https://www.mend.io/free-developer-tools/renovate/). View
repository job log
[here](https://developer.mend.io/github/openedx/edx-ui-toolkit).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy4yNDUuMCIsInVwZGF0ZWRJblZlciI6IjM3LjI0NS4wIiwidGFyZ2V0QnJhbmNoIjoibWFzdGVyIn0=-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package-lock.json

@@ -18,7 +18,7 @@
     "lint": "eslint ."
   },
   "dependencies": {
-    "backbone": "1.5.0",
+    "backbone": "1.6.0",
     "backbone.paginator": "2.0.8",
     "gulp-shell": "0.8.0",
     "jquery": "~3.7.0",