fix: Update README.md

[bxpana]

Discourse forum is on longer working so removed the links for now

[github-actions[bot]]

Visit the preview URL for this PR (updated for commit 6ac93fa):

• https://zksync-web-docs--v-refs-pull-317-merge-z4ru98xo.web.app
• https://staging-docs-zksync--v-refs-pull-317-merge-046w9zff.web.app

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[github-actions[bot]]

:tada: This PR is included in version 2.28.3 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: