[DEPENDABOT]: Bump panel from 0.12.7 to 0.13.1

Bumps [panel](https://github.com/holoviz/panel) from 0.12.7 to 0.13.1.
- [Release notes](https://github.com/holoviz/panel/releases)
- [Changelog](https://github.com/holoviz/panel/blob/master/CHANGELOG.md)
- [Commits](holoviz/panel@v0.12.7...v0.13.1)

---
updated-dependencies:
- dependency-name: panel
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>