Bump JamesIves/github-pages-deploy-action from 4.6.4 to 4.6.8

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](JamesIves/github-pages-deploy-action@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
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/deploy.yml

@@ -57,7 +57,7 @@ jobs:
           color=$(printf "%x%x%x" $((255-$percentage)) $((155+$percentage)) 85)
           opam exec -- ocb --style classic --label $label --status $percentage'%' --color $color > doc/coverage/badge.svg
       - name: deploy
-        uses: JamesIves/[email protected].4
+        uses: JamesIves/[email protected].8
         with:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           BRANCH: gh-pages