.github/workflows/code.yml: print rubocop version during tests

Output the active rubocop version before running the code linting
rules so that GitHub action logs clearly define which static analyzer
engine is being used.

Signed-off-by: Philip Li <philip.li@intel.com>

Author: rli9

.github/workflows/code.yml

@@ -30,6 +30,7 @@ jobs:
         with:
           ruby-version: ${{ matrix.ruby-version }}
           bundler-cache: true
+      - run: bundle exec rubocop -v
       - run: bundle exec rake code
 
   test-packages-debian: