chore(.toys): run bundle in external process to avoid Windows DLL collision (googleapis#26624)

fixes: googleapis#26615

Author: quartzmo

.toys/ci.rb

@@ -68,6 +68,9 @@ def run
 
 def run_in_dir dir
   Dir.chdir dir do
+    puts "\nRunning bundle install in #{dir}...", :bold
+    exec ["bundle", "install"]
+
     if include_spec
       puts
       puts "Running spec in #{dir}...", :bold