Pin the checkchange to the feature branch (#5611)

# Pull Request

## 📖 Description

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What problem does this change solve?
Is this a breaking change, chore, fix, feature, etc?
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This change will pin the `checkchange` check in the github workflow to check for changes against the `features/fast-element-2` branch. Since the branch should only be checking PRs against its contents and not the default branch this is the current workaround for checking for changefiles against non-default branches. This change must be removed prior to inclusion to the default branch.

## ✅ Checklist

### General

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- [ ] I have included a change request file using `$ yarn change`
- [ ] I have added tests for my changes.
- [x] I have tested my changes.
- [ ] I have updated the project documentation to reflect my changes.
- [x] I have read the [CONTRIBUTING](https://github.com/Microsoft/fast/blob/master/CONTRIBUTING.md) documentation and followed the [standards](https://www.fast.design/docs/community/code-of-conduct/#our-standards) for this project.

## ⏭ Next Steps

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If there is relevant follow-up work to this PR, please list any existing issues or provide brief descriptions of what you would like to do next.
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- Add an issue to remove this change in the feature branch tracking project (#5612)

package.json

@@ -43,7 +43,7 @@
   "scripts": {
     "bump": "beachball bump",
     "change": "beachball change",
-    "checkchange": "beachball check  --scope \"!sites/*\" --changehint \"Run 'yarn change' to generate a change file\"",
+    "checkchange": "beachball check  --scope \"!sites/*\" --changehint \"Run 'yarn change' to generate a change file\" -b origin/features/fast-element-2",
     "check": "beachball check ",
     "publish": "beachball publish",
     "publish-ci": "beachball publish -y --access public",