Bump tabulate from 0.8.8 to 0.8.9 (#593)

Bumps [tabulate](https://github.com/astanin/python-tabulate) from 0.8.8 to 0.8.9.
- [Release notes](https://github.com/astanin/python-tabulate/releases)
- [Changelog](https://github.com/astanin/python-tabulate/blob/master/CHANGELOG)
- [Commits](astanin/python-tabulate@v0.8.8...v0.8.9)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements_dev.txt

@@ -14,7 +14,7 @@ xarray==0.17.0
 netCDF4==1.5.6
 setuptools==41.2
 sdtfile==2020.12.10
-tabulate==0.8.8
+tabulate==0.8.9
 
 # documentation dependencies
 Sphinx>=3.2.0