Update git submodules
Update git submodules

* Update plugins/codemirror-editor from branch 'master'
  to e211fb1bd21043e2574c438a687c8f492d538c97
  - Move codemirror editor plugin to Polymer 3
    
    This migration still left the lazy load asset `codemirror-element`
    as a html module due to the selectively support on languages.
    
    Change-Id: I7896c86b59c75fe1967bc94d3d5c8d8d01150941
    
  - Remove support for Polymer 1
    
    We remove ShadyDom as we now user ShadowDom under Polymer 2+. We don't
    have the ShadyDom option switched on under Polymer 2 so this is not needed
    under Polymer 2+.
    
    Change-Id: Idab2da3fd7aed0a563c8e025ae9ddf20606d60b1
    
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