Fixes #5333

printFileSizesAfterBuild calls canReadAsset with an object containing
the file name while measureFileSizesBeforeBuild calls it with just the
name. When canReadAsset only receives the name it returns false since
accessing the `name` property results in undefined.

This commit fixes that by having canReadAssset instead expect only the
file name and making printFileSizesAfterBuild just like
measureFileSizesBeforeBuild only provide the name as argument.

* Fix broken link in main README

* Fix incorrect link in user guide README

It seems correct URL is https://developers.google.com/web/fundamentals/web-app-manifest/
Current URL (https://developers.google.com/web/fundamentals/engage-and-retain/web-app-manifest/) is redirecting to there.

* avoid TypeError on when registering service workers without config

Fixes #5299

* same before config.onUpdate

* add react-testing-library documentation/examples

* make react-testing-library a heading

* fix typo

 - babel-preset-react-app@5.0.3
 - create-react-app@2.0.3
 - react-dev-utils@6.0.4
 - react-error-overlay@5.0.4
 - react-scripts@2.0.4

* Caches the Yarn resolution for faster installs

* Adds the yarn.lock.cached file to the publish list

* Removes the copied lockfile when the install fails

* Updates the release checklist

* Add `.mjs` support back to webpack, because webpack was not the problem

* Continue toggling `.mjs` to `javascript/auto` mode

* Be more inline with the specification

* Bump old Node to 6

 - babel-plugin-named-asset-import@0.2.2
 - babel-preset-react-app@5.0.2
 - confusing-browser-globals@1.0.3
 - create-react-app@2.0.2
 - eslint-config-react-app@3.0.3
 - react-app-polyfill@0.1.3
 - react-dev-utils@6.0.3
 - react-error-overlay@5.0.3
 - react-scripts@2.0.3

Clicking Error overlay should feed the correct line number for gvim.

Added `gvim` in `COMMON_EDITORS_LINUX`, launches new gvim when it is running.

Tested with gvim 8.0.707 on a Debian 4.9.110-3+deb9u4 (2018-08-21) x86_64 GNU/Linux VM

Relates to https://github.com/facebook/create-react-app/issues/2636.

* Adds instructions to create a Bootstrap theme with Sass

* Update README.md

* Update README.md

* Update README.md

* Disable react/no-deprecated rule

* Changed wording

 - babel-plugin-named-asset-import@0.2.1
 - babel-preset-react-app@5.0.1
 - confusing-browser-globals@1.0.2
 - create-react-app@2.0.1
 - eslint-config-react-app@3.0.1
 - react-app-polyfill@0.1.2
 - react-dev-utils@6.0.2
 - react-error-overlay@5.0.2
 - react-scripts@2.0.2