Bump pytest-doctestplus from 0.9.0 to 0.10.0 (#792)

Bumps [pytest-doctestplus](https://github.com/astropy/pytest-doctestplus) from 0.9.0 to 0.10.0.
- [Release notes](https://github.com/astropy/pytest-doctestplus/releases)
- [Changelog](https://github.com/astropy/pytest-doctestplus/blob/main/CHANGES.rst)
- [Commits](scientific-python/pytest-doctestplus@0.9.0...v0.10.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

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

Author: dependabot[bot]

requirements_dev_optional.txt

@@ -15,7 +15,7 @@ tox==3.23.1
 coverage
 flake8==3.9.2
 pytest-cov==2.12.1
-pytest-doctestplus==0.9.0
+pytest-doctestplus==0.10.0
 h5py==3.2.1
 s3fs==2021.6.0
 fsspec==2021.6.0