Bump JamesIves/github-pages-deploy-action from 4.6.4 to 4.6.8 (#3018)

Bumps [JamesIves/github-pages-deploy-action](https://github.com/jamesives/github-pages-deploy-action) from 4.6.4 to 4.6.8.
- [Release notes](https://github.com/jamesives/github-pages-deploy-action/releases)
- [Commits](https://github.com/jamesives/github-pages-deploy-action/compare/v4.6.4...v4.6.8)

---
updated-dependencies:
- dependency-name: JamesIves/github-pages-deploy-action
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

.github/workflows/merge.yml

@@ -53,7 +53,7 @@ jobs:
         run: cargo doc --no-deps --workspace --all-features
 
       - name: Deploy
-        uses: JamesIves/github-pages-deploy-action@v4.6.4
+        uses: JamesIves/github-pages-deploy-action@v4.6.8
         with:
           branch: gh-pages
           folder: target/doc