Use a build matrix

.github/workflows/ruby.yml

@@ -1,18 +1,24 @@
 name: Ruby
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build:
 
     runs-on: ubuntu-latest
 
+    strategy:
+      matrix:
+        ruby: [2.4, 2.5, 2.6, 2.7, ruby-head]
+
     steps:
     - uses: actions/checkout@v1
-    - name: Set up Ruby 2.6
+
+    - name: Set up Ruby ${{ matrix.node }}
       uses: actions/setup-ruby@v1
       with:
-        ruby-version: 2.6.x
+        ruby-version: ${{ matrix.node }}
+
     - name: Cache gems
       uses: actions/cache@v1
       with:
@@ -20,15 +26,18 @@ jobs:
         key: ${{ runner.os }}-gem-${{ hashFiles('**/wpscan.gemspec') }}
         restore-keys: |
           ${{ runner.os }}-gem-
+
     - name: Build and test
       run: |
         gem install bundler
         bundle config force_ruby_platform true
         bundle config path vendor/bundle
         bundle install --jobs 4 --retry 3
+
     - name: test
       run: |
         bundle exec rspec
+
     - name: rubocop
       run: |
         bundle exec rubocop