Update yarn packages

This is just a periodic maintenance task- related to keeping out javascript tooling upto date.

a) run yarn outdated,
b) get all packages up to date.
c) rebuild our javascript
d) in patch review get into the messy business of analysing how things are going to break given those changes.

This issue is a spin off issue related to the closing of #2861497: Check in yarn.lock and recommend usage of yarn

As the issue was created here is the result of (a)

yarn outdated v1.3.2
info Color legend : 
 "<red>"    : Major Update backward-incompatible updates 
 "<yellow>" : Minor Update backward-compatible features 
 "<green>"  : Patch Update backward-compatible bug fixes
Package                        Current Wanted Latest Package Type    URL                                                               
babel-core                     6.24.1  6.24.1 6.26.0 devDependencies https://babeljs.io/                                               
babel-preset-env               1.4.0   1.4.0  1.6.1  devDependencies https://babeljs.io/                                               
chalk                          1.1.3   1.1.3  2.3.0  devDependencies https://github.com/chalk/chalk#readme                             
chokidar                       1.6.1   1.6.1  2.0.0  devDependencies https://github.com/paulmillr/chokidar                             
cross-env                      4.0.0   4.0.0  5.1.3  devDependencies https://github.com/kentcdodds/cross-env#readme                    
eslint                         3.19.0  3.19.0 4.16.0 devDependencies https://eslint.org                                                
eslint-config-airbnb           14.1.0  14.1.0 16.1.0 devDependencies https://github.com/airbnb/javascript                              
eslint-plugin-import           2.2.0   2.2.0  2.8.0  devDependencies https://github.com/benmosher/eslint-plugin-import                 
eslint-plugin-jsx-a11y         4.0.0   4.0.0  6.0.3  devDependencies https://github.com/evcohen/eslint-plugin-jsx-a11y#readme          
eslint-plugin-react            6.10.3  6.10.3 7.5.1  devDependencies https://github.com/yannickcr/eslint-plugin-react                  
glob                           7.1.1   7.1.1  7.1.2  devDependencies https://github.com/isaacs/node-glob#readme                        
stylelint                      7.10.1  7.13.0 8.4.0  devDependencies https://stylelint.io                                              
stylelint-checkstyle-formatter 0.1.0   0.1.1  0.1.1  devDependencies https://github.com/stylelint/stylelint-checkstyle-formatter#readme
stylelint-config-standard      16.0.0  16.0.0 18.0.0 devDependencies https://github.com/stylelint/stylelint-config-standard#readme     
stylelint-no-browser-hacks     1.0.2   1.1.0  1.1.0  devDependencies https://github.com/Slamdunk/stylelint-no-browser-hacks