[ANN] isolate 3.4.0 Released

isolate version 3.4.0 has been released!

* home: <http://github.com/jbarnette/isolate>

Isolate is a very simple RubyGems sandbox. It provides a way to
express and automatically install your project's Gem dependencies.

Changes:

### 3.4.0 / 2019-12-17

* 2 minor enhancements:

  * Switched multiruby default value to false.
  * Added logic to rebuild extensions as needed now that multiruby defaults to false.

* 3 bug fixes:

  * Remove empty path strings. This caused the #include? check to nuke everything.
  * Only remove paths that look like gem paths: absolute and end in "lib".
  * Fixed handling of path cleanup when system:false.