Bump pooch from 1.8.0 to 1.8.1 (#23)

Bumps [pooch](https://github.com/fatiando/pooch) from 1.8.0 to 1.8.1.
- [Release notes](https://github.com/fatiando/pooch/releases)
- [Changelog](https://github.com/fatiando/pooch/blob/main/doc/changes.rst)
- [Commits](fatiando/pooch@v1.8.0...v1.8.1)

---
updated-dependencies:
- dependency-name: pooch
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

requirements.txt

@@ -4,4 +4,4 @@ setuptools>=40.6.3
 scipy>=1.8
 matplotlib>=3.4.3
 scikit_learn>=0.23
-pooch==1.8.0
+pooch==1.8.1

setup.py

@@ -142,7 +142,7 @@
             "scipy>=1.8",
             "scikit_learn>=0.23",
             "matplotlib>=3.4.3",
-            "pooch==1.8.0"],
+            "pooch==1.8.1"],
     # List additional groups of dependencies here (e.g. development
     # dependencies). Users will be able to install these using the "extras"
     # syntax, for example: