Install scikit-learn<1.8.0 for minimum tests

Author: frances-h

.github/workflows/minimum.yml

@@ -31,5 +31,6 @@ jobs:
       run: |
           python -m pip install --upgrade pip
           python -m pip install invoke .[test]
+          python -m pip install "scikit-learn<1.8.0"
     - name: Test with minimum versions
       run: invoke minimum

tasks.py

@@ -101,10 +101,9 @@ def _get_minimum_versions(dependencies, python_version):
 @task
 def install_minimum(c):
     with open('pyproject.toml', 'rb') as pyproject_file:
-        pyproject_data = tomli.load(pyproject_file).get('project', {})
+        pyproject_data = tomli.load(pyproject_file)
 
-    dependencies = pyproject_data.get('dependencies', [])
-    dependencies += pyproject_data.get('optional-dependencies', {}).get('tutorials', [])
+    dependencies = pyproject_data.get('project', {}).get('dependencies', [])
     python_version = '.'.join(map(str, sys.version_info[:2]))
     minimum_versions = _get_minimum_versions(dependencies, python_version)