[CI] Ensure setuptools installed for tests

* To ensure that setuptools is available for setuptools.errors install
  it for all the tests in the CI.
   - setuptools.errors was added in v60.0.0
   - c.f. https://setuptools.pypa.io/en/latest/deprecated/distutils-legacy.html

Author: matthewfeickert

.github/workflows/build_tests.yml

@@ -35,7 +35,7 @@ jobs:
         pip install -e .
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
+        python -m pip install --upgrade pip setuptools
         pip install -r requirements.txt
         pip install pytest pytest-cov
     - name: Run tests
@@ -55,7 +55,7 @@ jobs:
         python-version: "3.10"
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
+        python -m pip install --upgrade pip setuptools
         pip install flake8 
     - name: Lint with flake8
       run: |
@@ -76,7 +76,7 @@ jobs:
         python-version: "3.10"
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
+        python -m pip install --upgrade pip setuptools
         pip install pytest pytest-cov
     - name: Install POT
       run: |
@@ -107,7 +107,7 @@ jobs:
          pip install -e .
      - name: Install dependencies
        run: |
-         python -m pip install --upgrade pip
+         python -m pip install --upgrade pip setuptools
          pip install -r requirements.txt
          pip install pytest 
      - name: Run tests

.github/workflows/build_wheels.yml

@@ -26,7 +26,7 @@ jobs:
 
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
+        python -m pip install --upgrade pip setuptools
 
     - name: Install cibuildwheel
       run: |
@@ -61,7 +61,7 @@ jobs:
 
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
+        python -m pip install --upgrade pip setuptools
 
     - name: Install cibuildwheel
       run: |

.github/workflows/build_wheels_weekly.yml

@@ -25,7 +25,7 @@ jobs:
 
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip
+        python -m pip install --upgrade pip setuptools
 
     - name: Install cibuildwheel
       run: |