refactor: fake time in CI using `dateoffset`

[dantengsky]

I hereby agree to the terms of the CLA available at: https://docs.databend.com/dev/policies/cla/

Summary

Fake time in CI using ·dateoffset·, which simulates time at the process level.

Tests

• [ ] Unit Test
• [ ] Logic Test
• [ ] Benchmark Test
• [x] No Test - tweak CI scripts

Type of change

• [ ] Bug Fix (non-breaking change which fixes an issue)
• [ ] New Feature (non-breaking change which adds functionality)
• [ ] Breaking Change (fix or feature that could cause existing functionality not to work as expected)
• [ ] Documentation Update
• [ ] Refactoring
• [ ] Performance Improvement
• [x] Other (please describe): weak CI scripts

---

This change is