Merge pull request saleor#3945 from mirumee/bump-backend-dependencies

Bump dependencies

Merge branch 'master' into demo

Update README.md

Merge pull request saleor#3817 from maarcingebala/update-demo

Update demo

Add tests for quantity and allocated quantity access

Merge pull request saleor#3693 from mirumee/fix-payment-redirects-to-…

…success-page

Redirect to success page after successful payment

Enable Braintree on demo

Revert package-lock.json

Merge pull request saleor#3699 from maarcingebala/update-demo

Update demo

Merge pull request saleor#3588 from maarcingebala/update-demo

Update demo