Disable routine dependabot version PRs

[mlafeldt]

PR #719 opened the fire hose inadvertently. We want security updates only.

[mlafeldt]

Cleanup

❯ for pr in 729 728 727 726 725 724 723 722 721 720 716 715; do gh pr close --repo duckdb/duckdb-rs $pr; done
✓ Closed pull request duckdb/duckdb-rs#729 (Bump zip from 6.0.0 to 7.2.0)
✓ Closed pull request duckdb/duckdb-rs#728 (Bump cc from 1.2.56 to 1.2.57)
✓ Closed pull request duckdb/duckdb-rs#727 (Bump darling from 0.20.11 to 0.21.3)
✓ Closed pull request duckdb/duckdb-rs#726 (Bump rand from 0.9.2 to 0.10.0)
✓ Closed pull request duckdb/duckdb-rs#725 (Bump strum from 0.27.2 to 0.28.0)
✓ Closed pull request duckdb/duckdb-rs#724 (Bump tar from 0.4.44 to 0.4.45)
✓ Closed pull request duckdb/duckdb-rs#723 (Bump polars from 0.49.1 to 0.53.0)
✓ Closed pull request duckdb/duckdb-rs#722 (Bump polars-core from 0.49.1 to 0.53.0)
✓ Closed pull request duckdb/duckdb-rs#721 (Bump calamine from 0.28.0 to 0.34.0)
✓ Closed pull request duckdb/duckdb-rs#720 (Bump hashlink from 0.10.0 to 0.11.0)
✓ Closed pull request duckdb/duckdb-rs#716 (Bump rustls-webpki from 0.103.9 to 0.103.10)
✓ Closed pull request duckdb/duckdb-rs#715 (Bump tar from 0.4.44 to 0.4.45)