Deployment: `ChildChainGaugeCheckpointer`

Deployment tasks checklist:

[x] Contract(s) deployed to all target networks / testnets
[x] TX IDs are properly generated
N/A Action IDs are generated after deployment (if applicable) --> checkpoint is permissionless
[x] Outputs for all target networks are generated, and linked in the task readme
[x] Addresses files are up to date with the new deployment
[x] Contracts are verified in every network --> ZKEVM pending for entrypoint
[x] Deployments CHANGELOG is updated
[ ] There are no code changes of any kind --> Minor fix to verify contracts properly in deployment script.

Closes #57.