Bump the all-deps group across 1 directory with 4 updates

Bumps the all-deps group with 4 updates in the / directory: [xtgeo](https://github.com/equinor/xtgeo), [ert](https://github.com/equinor/ert), [ruff](https://github.com/astral-sh/ruff) and [mypy](https://github.com/python/mypy).


Updates `xtgeo` from 4.20.0 to 4.21.0
- [Release notes](https://github.com/equinor/xtgeo/releases)
- [Changelog](https://github.com/equinor/xtgeo/blob/main/docs/release_notes.md)
- [Commits](equinor/xtgeo@4.20.0...4.21.0)

Updates `ert` from 21.0.7 to 21.0.9
- [Release notes](https://github.com/equinor/ert/releases)
- [Commits](equinor/ert@21.0.7...21.0.9)

Updates `ruff` from 0.15.10 to 0.15.12
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.15.10...0.15.12)

Updates `mypy` from 1.20.1 to 1.20.2
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.20.1...v1.20.2)

---
updated-dependencies:
- dependency-name: xtgeo
  dependency-version: 4.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: all-deps
- dependency-name: ert
  dependency-version: 21.0.9
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: all-deps
- dependency-name: ruff
  dependency-version: 0.15.12
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: all-deps
- dependency-name: mypy
  dependency-version: 1.20.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: all-deps
...

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Author: dependabot[bot]