Bump pandas from 1.0.3 to 1.0.4
Bump pandas from 1.0.3 to 1.0.4

Bumps [pandas](https://github.com/pandas-dev/pandas) from 1.0.3 to 1.0.4.
- [Release notes](https://github.com/pandas-dev/pandas/releases)
- [Changelog](https://github.com/pandas-dev/pandas/blob/master/RELEASE.md)
- [Commits](https://github.com/pandas-dev/pandas/compare/v1.0.3...v1.0.4)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
vega/ipython-vega,uwdata/ipython-vega-lite,uwdata/ipython-vega-lite,vega/ipyvega,uwdata/ipython-vega,uwdata/ipython-vega,vega/ipyvega,vega/ipython-vega,uwdata/ipython-vega,vega/ipyvega,vega/ipython-vega,uwdata/ipython-vega-lite,vega/ipyvega