Upgrade bundler to fight against bundler bug

.gitlab/ci/rails.gitlab-ci.yml

@@ -393,8 +393,7 @@ db:migrate-from-previous-major-version:
     - sed -i -e "s/gem 'google-protobuf', '~> 3.8.0'/gem 'google-protobuf', '~> 3.12'/" Gemfile
     - sed -i -e "s/gem 'nokogiri', '~> 1.10.5'/gem 'nokogiri', '~> 1.11.0'/" Gemfile
     - sed -i -e "s/gem 'mimemagic', '~> 0.3.2'/gem 'ruby-magic', '~> 0.4.0'/" Gemfile
-    - run_timed_command "gem install bundler:1.17.3"
-    - run_timed_command "bundle update google-protobuf nokogiri grpc mimemagic bootsnap"
+    - run_timed_command "bundle update --bundler google-protobuf nokogiri grpc mimemagic bootsnap"
     - SETUP_DB=false USE_BUNDLE_INSTALL=true bash scripts/prepare_build.sh
     - run_timed_command "bundle exec rake db:drop db:create db:structure:load db:migrate db:seed_fu"
     - git checkout -f $CI_COMMIT_SHA