chore: Remove link to Slack

Author: igorlukanin

website/docusaurus.config.js

@@ -69,11 +69,6 @@ const config = {
             position: 'left',
             label: 'Examples',
           },
-          {
-            href: 'https://slack.cube.dev/?ref=eco-react-chartjs',
-            label: 'Slack',
-            position: 'right',
-          },
           {
             href: 'https://stackoverflow.com/questions/tagged/react-chartjs-2',
             label: 'Stack Overflow',