fix: Update README.md

[bxpana]

Update Capabilities section to include link to the zkSync 2.0 docs and mention the zkSync 2.0 testnet

[github-actions[bot]]

Visit the preview URL for this PR (updated for commit 0c27753):

• https://zksync-web-docs--v-refs-pull-292-merge-39uv7d91.web.app
• https://staging-docs-zksync--v-refs-pull-292-merge-p7xbwff8.web.app

_{(expires Fri, 24 Jun 2022 19:27:30 GMT)}

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[github-actions[bot]]

:tada: This PR is included in version 2.22.5 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: