vue-storefront

Update README.md

##Related issues

helps with #1273

##Short description and why it's useful

Updated the supported browsers list.
#Screenshots of visual changes before/after (if there are any)

##Which environment this relates to

##Check your case. In case of any doubts please read about Release Cycle

  Test version (https://test.storefrontcloud.io) - this is a new feature or improvement for Vue Storefront. I've created branch from develop branch and want to merge it back to develop
  RC version (https://next.storefrontcloud.io) - this is a stabilisation fix for Release Candidate of Vue Storefront. I've created branch from release branch and want to merge it back to release
  Stable version (https://demo.storefrontcloud.io) - this is an important fix for current stable version. I've created branch from hotfix or master branch and want to merge it back to hotfix
Upgrade Notes and Changelog

  No upgrade steps required (100% backward compatibility and no breaking changes)
  I've updated the Upgrade notes and Changelog on how to port existing VS sites with this new feature
IMPORTANT NOTICE - Remember to update CHANGELOG.md with description of your change

##Contribution and currently important rules acceptance

  I read and followed contribution rules
  I read the TypeScript Action Plan and adjusted my PR according to it
  I read about Vue Storefront Modules and I am aware that every new feature should be a module