Bump docker/login-action from 3 to 4

Bumps [docker/login-action](https://github.com/docker/login-action) from 3 to 4.
- [Release notes](https://github.com/docker/login-action/releases)
- [Commits](https://github.com/docker/login-action/compare/v3...v4)

---
updated-dependencies:
- dependency-name: docker/login-action
  dependency-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/build.yml

@@ -154,7 +154,7 @@ jobs:
             ${{steps.tagger.outputs.latest}}
       - run: echo "${GITHUB_REF#refs/heads/}-${{steps.tagger.outputs.describe}}" > .nightly
       - run: cat .nightly
-      - uses: docker/login-action@v3
+      - uses: docker/login-action@v4
         if: ${{ github.repository == 'znc/znc' && github.event_name == 'push' }}
         with:
           username: ${{ secrets.DOCKER_USERNAME }}