squash: remove superfluous attribute

Author: arielvalentin

.github/actions/test_gem/action.yml

@@ -90,7 +90,6 @@ runs:
         bundler:  "latest"
         bundler-cache: false
         cache-version: "${{ inputs.ruby }}-${{ steps.setup.outputs.cache_key }}-${{ inputs.gem }}"
-        run: bundle install
 
     # If we're using appraisals, do it all manually.
     - name: Install Ruby ${{ inputs.ruby }} without dependencies