gems: update rubocop requirement from ~> 1.85.0 to ~> 1.86.0

Updates the requirements on [rubocop](https://github.com/rubocop/rubocop) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop/releases)
- [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubocop/rubocop/compare/v1.85.0...v1.86.0)

---
updated-dependencies:
- dependency-name: rubocop
  dependency-version: 1.86.0
  dependency-type: direct:development
...

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

.github/workflows/cd.yml

@@ -33,7 +33,7 @@ jobs:
 
     # https://github.com/marketplace/actions/build-and-push-docker-images
     - name: Set up Docker Buildx
-      uses: docker/setup-buildx-action@v3
+      uses: docker/setup-buildx-action@v4
 
     - name: Login to Docker Hub
       uses: docker/login-action@v4
@@ -42,7 +42,7 @@ jobs:
         password: ${{ secrets.DOCKER_TOKEN }}
 
     - name: Build and push Docker image for dyndnsd ${{ env.DYNDNSD_VERSION }}
-      uses: docker/build-push-action@v6
+      uses: docker/build-push-action@v7
       with:
         context: docker
         build-args: |

dyndnsd.gemspec

@@ -44,7 +44,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rack-test'
   s.add_development_dependency 'rake'
   s.add_development_dependency 'rspec'
-  s.add_development_dependency 'rubocop', '~> 1.85.0'
+  s.add_development_dependency 'rubocop', '~> 1.86.0'
   s.add_development_dependency 'rubocop-rake', '~> 0.7.1'
   s.add_development_dependency 'rubocop-rspec', '~> 3.9.0'
   s.add_development_dependency 'solargraph', '~> 0.58.1'