fix: Withdrawal delay (#325)

<!--

Thank you for contributing to the ZKsync Docs!

Before submitting the PR, please make sure you do the following:

- Update your PR title to follow [Conventional
Commits](https://www.conventionalcommits.org/en/v1.0.0/)
- Read the [Contributing
Guide](https://github.com/matter-labs/zksync-docs/blob/main/CONTRIBUTING.md).
- Understand our [Code of
Conduct](https://github.com/matter-labs/zksync-docs/blob/main/CODE_OF_CONDUCT.md)
- Please delete any unused parts of the template when submitting your PR

-->

# Description

Updated section about the withdrawal delay to reflect the new changes in
[ZIP-4](https://forum.zknation.io/t/zip-4-reduce-the-execution-delay-from-21-hours-to-3-hours/373)

## Linked Issues

Fixes matter-labs/dapp-portal#219

## Additional context

content/20.zksync-protocol/60.security/30.withdrawal-delay.md

@@ -9,8 +9,15 @@ effects of the transactions included in a block before the block becomes final.
 any anomaly (e.g. rapid outflow, unusually large withdrawals, etc).
 
 To introduce this time lock, no changes were made to the audited smart contracts. Instead, we have used an existing Validator role that we control
-and that we further restricted by pointing it to an intermediate smart contract with a time lock. The time lock is initially configured for a
-**24-hour** delay, which will gradually decrease as the system matures. Changing the delay requires a governance proposal approved by the community.
+and that we further restricted by pointing it to an intermediate smart contract
+with a time lock. The time lock across supported ZK chains has been reduced from
+21 hours to a **3 hour minimum** as detailed in
+[ZIP-4: Reduce the execution delay from 21 hours to 3
+hours](https://forum.zknation.io/t/zip-4-reduce-the-execution-delay-from-21-hours-to-3-hours/373).
+This change does not
+guarantee that batches will always be finalized on L1 within 3 hours, the actual
+finalization time depends on network activity and proof generation. Changing the
+delay further requires a governance proposal approved by the community.
 
 This design has the following advantages: