[JTH] add stats dependency for documentation

Author: tausiaj

.github/workflows/build-docs.yml

@@ -24,6 +24,7 @@ jobs:
       - name: Install dependencies
         run: |
           pip install bluemath-tk[docs]
+          pip install bluemath-tk[stats]
 
       - name: Sphinx build
         run: |

.github/workflows/python-tests.yml

@@ -34,7 +34,7 @@ jobs:
         run: |
           source /usr/share/miniconda/etc/profile.d/conda.sh
           conda activate bluemath-tk
-          pip install bluemath-tk
+          pip install bluemath-tk[stats]
           pip install ruff
 
       - name: Run Ruff