Explicitly call bundle install

Bundler 4.0 changes the behaviour of a bare call to `bundle` to print
help rather than running `bundle install`.

See ruby/rubygems#8786

Author: mudge

Rakefile

@@ -76,7 +76,7 @@ namespace :gem do
         sudo apt-get install -y cmake=3.22.2-0kitware1ubuntu20.04.1 cmake-data=3.22.2-0kitware1ubuntu20.04.1 &&
         rbenv shell 3.1.6 &&
         gem install bundler --no-document &&
-        bundle &&
+        bundle install &&
         bundle exec rake native:#{platform} pkg/#{re2_gemspec.full_name}-#{Gem::Platform.new(platform)}.gem PATH="/usr/local/bin:$PATH"
       SCRIPT
     end

scripts/test-gem-install

@@ -4,5 +4,5 @@ set -eu
 
 gem install --no-document pkg/*.gem -- "$@"
 cd "$(dirname "$(gem which re2)")/.."
-bundle
+bundle install
 bundle exec rake spec