Update grunt-contrib-compress to 0.12.0

Upstream changes https://github.com/gruntjs/grunt-contrib-compress/compare/f0762ba6e265ec768e65af07fc96512bd8798080...v0.12.0

see #30141



git-svn-id: https://develop.svn.wordpress.org/trunk@30060 602fd350-edb4-49c9-b593-d223f7449a82