chore: Bump actions/upload-artifact from 4 to 7

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 4 to 7.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v4...v7)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/elixir.yml

@@ -176,7 +176,7 @@ jobs:
           echo "${{ github.event.pull_request.head.sha }}" > cover/PR_SHA
         if: github.event.pull_request
       - name: Upload coverage artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: elixir-lcov
           path: cover/