Dockerfile in quiz_api_client-3.2.0 vs Dockerfile in quiz_api_client-4.0.0

@@ -2,10 +2,11 @@
 
 RUN mkdir -p coverage log pacts
 
 COPY --chown=docker:docker quiz_api_client.gemspec Gemfile ./
 COPY --chown=docker:docker lib/quiz_api_client/version.rb lib/quiz_api_client/version.rb
-RUN /bin/bash -l -c "rvm-exec 2.4 bundle install --jobs 5"
+RUN /bin/bash -l -c "rvm-exec 2.6 gem install bundler -v 2.1.4"
+RUN /bin/bash -l -c "rvm-exec 2.6 bundle install --jobs 5"
 
 COPY --chown=docker:docker . .
 
-CMD /bin/bash -l -c "rvm-exec 2.4 bundle exec rspec"
+CMD /bin/bash -l -c "rvm-exec 2.6 bundle exec rspec"