ci: run rubocop in a different job

Also only run `rubocop` against `Ruby 3.4`

Author: nicolastemciuc

.github/workflows/build.yml

@@ -10,6 +10,21 @@ name: build
 on: push
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out repository code
+        uses: actions/checkout@v4
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.4'
+          bundler-cache: true
+
+      - name: Lint code for consistent style
+        run: bundle exec rubocop -f github
   test:
     runs-on: ubuntu-20.04
     strategy:
@@ -62,4 +77,4 @@ jobs:
       with:
         ruby-version: ${{ matrix.ruby }}
         bundler-cache: true
-    - run: bundle exec rake
+    - run: bundle exec rspec