W3c validation error aria-polite

Problem/Motivation

There is a W3c validation error with atributte aria-polite because it doesn't exist for aria properties.

Proposed resolution

You can fix it change aria-polite by aria-live in twitter_block/src/Plugin/Block/TwitterBlock.php. Here I paste the new code:
Line 255
+ $render['block']['#attributes']['aria-live'] = $config['polite'];
- $render['block']['#attributes']['aria-polite'] = $config['polite'];