Update ChangeLog for version 3.0.0 release

[xuantuan58]

Summary

• Added changelog entries for version 3.0.0 release
• Documented all changes since v2.0.0 including API updates, dependency updates, and CI improvements

Changes included:

• Remove partial_delete API (Remove partial_delete api #153)
• Support trino type query. Add CI test for Ruby 3.3 & 3.4 (Support trino type query. Add CI test for Ruby 3.3 & 3.4 #152)
• Clean up test certs (Clean up test certs #149)
• Update API responses for table list, schedule list, result list, database list APIs
• Add id, user_id, and description to the /database/list API (Update the response for the list database api #145)
• Update webmock requirement from ~> 3.18.1 to ~> 3.25.1 (Update webmock requirement from ~> 3.18.1 to ~> 3.25.1 #150)
• Remove old CI badges from README (Remove old CI badges from README #143)
• Add Circleci with coveralls support (Circleci with coveralls #141)

Test plan

• Verify changelog format matches existing entries
• All changes since v2.0.0 are documented
• Review and approve changelog content