github-actions: bump docker/login-action from 1 to 2 (#8425)

Bumps [docker/login-action](https://github.com/docker/login-action) from 1 to 2.
- [Release notes](https://github.com/docker/login-action/releases)
- [Commits](https://github.com/docker/login-action/compare/v1...v2)

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

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

.github/workflows/docker.yml

@@ -77,7 +77,7 @@ jobs:
 
     - name: Login to DockerHub
       if: success() && github.repository == 'openthread/openthread' && github.event_name != 'pull_request'
-      uses: docker/login-action@v1
+      uses: docker/login-action@v2
       with:
         username: ${{ secrets.DOCKER_USERNAME }}
         password: ${{ secrets.DOCKER_PASSWORD }}