Update code scanning alert

[adrienpessu]

This pull request introduces a new feature for updating code scanning alerts in a GitHub repository. The most important changes include adding a new module for handling updates, defining a new enum for alert states, and creating a test to verify the update functionality.

New Feature: Update Code Scanning Alerts

• src/api/code_scannings.rs: Added the update module and the update method to the CodeScanningHandler to handle updating code scanning alerts. [1] [2]
• src/api/code_scannings/update.rs: Implemented the UpdateCodeScanningBuilder struct, which includes methods for setting the state, dismissed reason, and dismissed comment of a code scanning alert, and a send method to execute the update.
• src/params.rs: Added the AlertState enum to represent the state of a code scanning alert, with possible values Dismissed and Open.
• tests/code_scanning_alert_update_test.rs: Created a test to verify that the update method correctly updates a code scanning alert and handles a successful response.

[XAMPPRocky]

Thank you for your PR!