chore: bump wherobots-python-dbapi pin to >=0.28.0 and version to 1.7.0

[ClayMav]

Summary

• Bump wherobots-python-dbapi floor in pyproject.toml from >=0.26.1 to >=0.28.0.
• Bump airflow-providers-wherobots version from 1.6.1 to 1.7.0 (release vehicle for feat: accept str|enum region/runtime, omit when unset for org default #57).
• Refresh uv.lock so the package actually resolves to dbapi 0.28.0.

Why now

PR #57 widened region/runtime to str | enum | None on WherobotsRunOperator / WherobotsSqlOperator and stopped injecting hardcoded aws-us-west-2/tiny defaults, but left the dbapi floor at >=0.26.1 so the PR's CI could resolve before dbapi v0.28.0 was published. v0.28.0 is now on PyPI and includes the matching client-side change — strings (BYOC included) pass through to the API as-is, and omitted values let the API apply the org's configured default.

Without this bump, an installer of airflow-providers-wherobots>=1.6.1 could still resolve to the old enum-only dbapi 0.26.1 / 0.27.0 and crash on raw BYOC region strings via Region(value).

Compatibility

• Existing DAGs passing Region.X / Runtime.X enums continue to work — their .value is used at the request boundary.
• Existing DAGs that omitted region / runtime will now follow the org's configured default instead of the previous hardcoded aws-us-west-2 / tiny. If you depended on the old hardcoded values, pass them explicitly.

Test plan

• Locally installed against staging dbapi 0.28.0; tests/unit_tests/operators/test_helpers.py::TestWarnForDefaultRegion passes (3/3) and region/runtime-focused operator tests pass (9 collected).
• Hook-level smoke against staging: WherobotsRestAPIHook.create_run with no region → aws-eu-west-1 (org default); raw BYOC string aws-us-east-1-djrm9bs9uf → passthrough; Region enum → .value resolved.
• After merge + tag + release, confirm pypi-publish.yaml succeeds and pip index versions airflow-providers-wherobots shows 1.7.0.
• Confirm prod-targeted integration suite stays green on main post-release.