Rename "Ruby" action to "Test", and add Rubocop action

Author: scottrobertson

.github/workflows/rubocop.yml

@@ -0,0 +1,16 @@
+name: Rubocop
+
+on: push
+
+jobs:
+  rubocop:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 2.7
+      - run: gem install bundler -v 2.2.4
+      - run: bundle install
+      - run: bundle exec rubocop

.github/workflows/test.yml

@@ -1,4 +1,4 @@
-name: Ruby
+name: Test
 
 on: push