Dependabot update

CLA: trivial

(deps): Bump coverallsapp/github-action

Bumps [coverallsapp/github-action](https://github.com/coverallsapp/github-action) from 2.3.6 to 2.3.8.
- [Release notes](https://github.com/coverallsapp/github-action/releases)
- [Commits](https://github.com/coverallsapp/github-action/compare/648a8eb78e6d50909eff900e4ec85cab4524a45b...8d6379e14d29928660c4ba802d8e85393440b329)

---
updated-dependencies:
- dependency-name: coverallsapp/github-action
  dependency-version: 2.3.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

.github/workflows/coveralls.yml

diff --git a/.github/workflows/coveralls.yml b/.github/workflows/coveralls.yml
index 34075a3..d32bf65 100644
--- a/.github/workflows/coveralls.yml
+++ b/.github/workflows/coveralls.yml
@@ -121,7 +121,7 @@
              --branch-coverage
               -o ./lcov.info
     - name: Coveralls upload
-      uses: coverallsapp/github-action@648a8eb78e6d50909eff900e4ec85cab4524a45b #v2.3.6
+      uses: coverallsapp/github-action@8d6379e14d29928660c4ba802d8e85393440b329 #v2.3.8
       with:
         github-token: ${{ secrets.github_token }}
         git-branch: ${{ matrix.branches.branch }}