ci: fix python version reference

Author: vdusek

.github/workflows/build_and_deploy_docs.yaml

@@ -55,7 +55,7 @@ jobs:
 
       - name: Install Python dependencies
         run: |
-          pipx install --python ${{ matrix.python-version }} poetry
+          pipx install --python ${{ env.PYTHON_VERSION }} poetry
           make install-dev
 
       - name: Build generated API reference

.github/workflows/run_release.yaml

@@ -98,7 +98,7 @@ jobs:
 
       - name: Install Python dependencies
         run: |
-          pipx install --python ${{ matrix.python-version }} poetry
+          pipx install --python ${{ env.PYTHON_VERSION }} poetry
           make install-dev
 
       - # Determine if this is a prerelease or latest release