Fix/drop ruby 2 support gemfile

.github/workflows/ci.yml

@@ -1,30 +1,13 @@
 name: CI
 
-on:
-  - pull_request
-  - push
+on: pull_request
+
+concurrency:
+  group: ${{ github.ref_name }}-${{ github.workflow }}
+  cancel-in-progress: true
 
 jobs:
   test:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        ruby:
-          - "2.5"
-          - "2.6"
-          - "2.7"
-    name: Ruby ${{ matrix.ruby }}
-    steps:
-      - uses: actions/checkout@v3
-      - name: Install development headers
-        run: sudo apt install libkrb5-dev libldap-dev libsasl2-dev -y
-      - name: Install Ruby ${{ matrix.ruby }}
-        uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: ${{ matrix.ruby }}
-          bundler-cache: true
-      - name: Run tests
-        run: bundle exec rake test
-      - name: Verify gem builds
-        run: gem build *.gemspec
+    name: Tests
+    uses: theforeman/actions/.github/workflows/smart_proxy_plugin.yml@v0
+

Gemfile

@@ -2,11 +2,6 @@ source 'https://rubygems.org'
 gemspec
 
 group :development do
-  if RUBY_VERSION < '2.2.2'
-    gem 'rack-test', '~> 0.7.0'
-  else
-    gem 'rack-test'
-  end
-
+  gem 'rack-test'
   gem 'smart_proxy', :git => 'https://github.com/theforeman/smart-proxy.git', :branch => 'develop'
 end