Update .github/workflows/validation.yml

Co-authored-by: Chris Markiewicz <[email protected]>

Author: Remi-Gau

.github/workflows/validation.yml

@@ -20,9 +20,5 @@ jobs:
     - uses: actions/setup-python@v5
       with:
         python-version: 3
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip setuptools
-        pip3 install cffconvert
     - name: Validate CITATION.cff
-      run: cffconvert --validate
+      run: pipx run cffconvert --validate